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Sample records for shergottites dar al

  1. Exposure History of Shergottites Dar Al Gani 476/489/670/735 and Sayh Al Uhaymir 005

    SciTech Connect

    Nishiizumi, N.; Caffee, M.; Jull, A.J.T.; Klandrud, S.E.

    2001-04-01

    Four basaltic shergottites, Dar al Gani (DaG) 476, 489, 670, and 735 were found in the Libyan Sahara [1-3]; two basaltic shergottites, Sayh al Uhaymir (SaU) 005 and 008 were found in Oman [4]. Recently SaU 051 was also recognized as a possible pair of SaU 005/008. Although the collection sites were different, the texture, bulk chemical compositions, and noble gas compositions of these shergottites are similar [e.g. 4]. However, cosmic-ray-produced noble gases alone cannot unambiguously constrain the irradiation history for these objects. From a combination of cosmogenic stable- and radionuclides, exposure histories, and ejection conditions from the hypothesized Martian parent body, and genetic relationships between the Martian meteorites can be determined. In addition to those nuclides produced by galactic cosmic rays (GCR) are those produced by solar cosmic rays (SCR). Radionuclides produced by SCRs reside in the uppermost few centimeters of extraterrestrial bodies and their presence in meteorites indicates the degree to which a meteorite has been ablated. Previous work shows ablation is less than 1-2 cm in at least three shergottites, ALH 77005, Shergotty, and EETA79001 [e.g. 5] and so it is possible some SCR signal may be observed in these meteorites. This suggests that the atmospheric entry velocity and/or entry angle of these shergottites is much lower than the velocity and/or entry angle of most ordinary chondrites. We report here preliminary results of cosmogenic nuclides, {sup 14}C (half-life = 5,730 yr), {sup 36}Cl (3.01 x 10{sup 5} yr), {sup 26}Al (7.05 x 10{sup 5} yr), and {sup 10}Be(1.5 x 10{sup 6} yr).

  2. Exposure history of shergottites

    NASA Technical Reports Server (NTRS)

    Nishizumi, K.; Arnold, J. R.; Klein, J.; Middleton, R.; Elmore, D.

    1986-01-01

    The cosmogenic nuclides Cl-36, Al-26, Be-10, and Mn-53 were analyzed in Shergotty, ALHA 77005, and EETA 79001 shergottites by means of accelerator mass spectrometry and neutron activation. The cosmogenic radionuclide data were combined with noble gas data and cosmic ray track data to obtain the exposure ages, terrestrial ages, preatmospheric radii, and ablation depths for the three shergottites. The results indicate that none of the three meteorites was irradiated measurably by cosmic rays on its parent body, and that all three objects were ejected from greater than a 3-m depth in their parent bodies. The EETA 79001 meteorite was ejected in an event distinct from that of ALHA 77005 and Shergotty. All three shergottites show a very small amount of ablation, suggesting low velocities on entry into the earth's atmosphere.

  3. Cosmogenic Records in 18 Ordinary Chondrites from the Dar Al Gani Region, Libya. 2; Radionclides

    NASA Technical Reports Server (NTRS)

    Welten, K. C.; Nishiizumi, K.; Finkel, R. C.; Hillegonds, D. J.; Jull, A. J. T.; Schultz, L.

    2003-01-01

    In the past decade more than 1000 meteorites have been recovered from the Dar al Gani (DaG) plateau in the Libyan part of the Sahara. The geological setting, meteorite pairings and density are described. So far, only a few terrestrial ages are known for DaG meteorites, e.g. 60+/- 20 kyr for the DaG 476 shergottite shower and 80+/- 20 kyr for the lunar meteorite DaG 262. However, from other desert areas, such as Oman, it is known that achondrites may survive much longer than chondritic meteorites, so the ages of these two achondrites may not be representative of the majority of the DaG meteorite collection, of which more than 90% are ordinary chondrites. In this work we report concentrations of the cosmogenic radionuclides, 14C (half-life = 5,730 yr), 41Ca (1.04x10 superscript 5 yr), Cl-36 (3.01x10 superscript 5 yr), Al-26 (7.05x10 superscript 5 yr) and 10Be (1.5x10 superscript 6 yr) to determine the terrestrial ages of DaG meteorites and constrain their pre-atmospheric size and exposure history.

  4. Petrogenesis of olivine-phyric shergottites Sayh al Uhaymir 005 and Elephant Moraine A79001 lithology A

    NASA Astrophysics Data System (ADS)

    Goodrich, Cyrena Anne

    2003-10-01

    Martian meteorites Sayh al Uhaymir (SaU) 005 and lithology A of EETA79001 (EET-A) belong to a newly emerging group of olivine-phyric shergottites. Previous models for the origin of such shergottites have focused on mixing between basaltic shergottite-like magmas and lherzolitic shergottite-like material. Results of this work, however, suggest that SaU 005 and EET-A formed from olivine-saturated magmas that may have been parental to basaltic shergottites. SaU 005 and EET-A have porphyritic textures of large (up to ˜3 mm) olivine crystals (˜25% in SaU 005; ˜13% in EET-A) in finer-grained groundmasses consisting principally of pigeonite (˜50% in SaU 005; ˜60% in EET-A), plagioclase (maskelynite) and < 7% augite. Low-Ti chromite occurs as inclusions in the more magnesian olivine, and with chromian ulvöspinel rims in the more ferroan olivine and the groundmass. Crystallization histories for both rocks were determined from petrographic features (textures, crystal shapes and size distributions, phase associations, and modal abundances), mineral compositions, and melt compositions reconstructed from magmatic inclusions in olivine and chromite. The following observations indicate that the chromite and most magnesian olivine (Fo 74-70 in SaU 005; Fo 81-77 in EET-A) and pyroxenes (low-Ca pyroxene [Wo 4-6] of mg 77-74 and augite of mg 78 in SaU 005; orthopyroxene [Wo 3-5] of mg 84-80 in EET-A) in these rocks are xenocrystic. (1) Olivine crystal size distribution (CSD) functions show excesses of the largest crystals (whose cores comprise the most magnesian compositions), indicating addition of phenocrysts or xenocrysts. (2) The most magnesian low-Ca pyroxenes show near-vertical trends of mg vs. Al 2O 3 and Cr 2O 3, which suggest reaction with a magma. (3) In SaU 005, there is a gap in augite composition between mg 78 and 73. (4) Chromite cores of composite spinel grains are riddled with cracks, indicating that they experienced some physical stress before being overgrown

  5. Geochemistry of intermediate olivine-phyric shergottite Northwest Africa 6234, with similarities to basaltic shergottite Northwest Africa 480 and olivine-phyric shergottite Northwest Africa 2990

    NASA Astrophysics Data System (ADS)

    Filiberto, Justin; Chin, Emily; Day, James M. D.; Franchi, Ian A.; Greenwood, Richard C.; Gross, Juliane; Penniston-Dorland, Sarah C.; Schwenzer, Susanne P.; Treiman, Allan H.

    2012-08-01

    The newly found meteorite Northwest Africa 6234 (NWA 6234) is an olivine (ol)-phyric shergottite that is thought, based on texture and mineralogy, to be paired with Martian shergottite meteorites NWA 2990, 5960, and 6710. We report bulk-rock major- and trace-element abundances (including Li), abundances of highly siderophile elements, Re-Os isotope systematics, oxygen isotope ratios, and the lithium isotope ratio for NWA 6234. NWA 6234 is classified as a Martian shergottite, based on its oxygen isotope ratios, bulk composition, and bulk element abundance ratios, Fe/Mn, Al/Ti, and Na/Al. The Li concentration and δ7Li value of NWA 6234 are similar to that of basaltic shergottites Zagami and Shergotty. The rare earth element (REE) pattern for NWA 6234 shows a depletion in the light REE (La-Nd) compared with the heavy REE (Sm-Lu), but not as extreme as the known "depleted" shergottites. Thus, NWA 6234 is suggested to belong to a new category of shergottite that is geochemically "intermediate" in incompatible elements. The only other basaltic or ol-phyric shergottite with a similar "intermediate" character is the basaltic shergottite NWA 480. Rhenium-osmium isotope systematics are consistent with this intermediate character, assuming a crystallization age of 180 Ma. We conclude that NWA 6234 represents an intermediate compositional group between enriched and depleted shergottites and offers new insights into the nature of mantle differentiation and mixing among mantle reservoirs in Mars.

  6. Crystallization kinetics of olivine-phyric shergottites

    NASA Astrophysics Data System (ADS)

    Ennis, Megan E.; McSween, Harry Y.

    2014-08-01

    Crystal size distribution (CSD) and spatial distribution pattern (SDP) analyses are applied to the early crystallizing phases, olivine and pyroxene, in olivine-phyric shergottites (Elephant moraine [EET] 79001A, Dar al Gani [DaG] 476, and dhofar [Dho] 019) from each sampling locality inferred from Mars ejection ages. Trace element zonation patterns (P and Cr) in olivine are also used to characterize the crystallization history of these Martian basalts. Previously reported 2-D CSDs for these meteorites are re-evaluated using a newer stereographically corrected methodology. Kinks in the olivine CSD plots suggest several populations that crystallized under different conditions. CSDs for pyroxene in DaG 476 and EET 79001A reveal single populations that grew under steady-state conditions; pyroxenes in Dho 019 were too intergrown for CSD analysis. Magma chamber residence times of several days for small grains to several months for olivine megacrysts are calculated using the CSD slopes and growth rates inferred from previous experimental data. Phosphorus imaging in olivines in DaG 476 and Dho 019 indicate rapid growth of skeletal, sector-zoned, or patchy cores, probably in response to delayed nucleation, followed by slow growth, and finally rapid dendritic growth with back-filling to form oscillatory zoning in rims. SPD analyses indicate that olivine and pyroxene crystals grew or accumulated in clusters rather than as randomly distributed grains. These data reveal complex solidification histories for Martian basalts, and are generally consistent with the formation at depth of olivine megacryst cores, which were entrained in ascending magmas that crystallized pyroxenes, small olivines, and oscillatory rims on megacrysts.

  7. Cosmogenic Records in 18 Ordinary Chondrites from the Dar Al Gani Region, Libya. 1; Noble Gases

    NASA Technical Reports Server (NTRS)

    Schultz, L.; Franke, L.; Welten, K. C.; Nishiizumi, K.; Jull, A. J. T.

    2003-01-01

    In the last decade thousands of meteorites have been recovered from hot deserts in the Sahara and Oman. One of the main meteorite concentration surfaces in the Sahara is the Dar al Gani plateau in Libya, which covers a total area of 8000 km2. More than 1000 meteorites have been reported from this area. The geological setting, meteorite pairings and the meteorite density of the Dar al Gani (DaG) field are described in more detail in [1]. In this work we report concentrations of the noble gas isotopes of He, Ne, Ar as well as 84Kr and 132Xe in 18 DaG meteorites. In a separate paper we will report the cosmogenic radionuclides [2]. We discuss the thermal history and cosmic-ray exposure (CRE) history of these meteorites, and evaluate the effects of the hot desert environment on the noble gas record.

  8. Solubility of Sulfur in Shergottitic Silicate Melts Up to 0.8 GPA: Implications for S Contents of Shergottites

    NASA Technical Reports Server (NTRS)

    Righter, K.; Pando, K.M.; Danielson, L.

    2009-01-01

    Shergottites have high S contents (1300 to 4600 ppm; [1]), but it is unclear if they are sulfide saturated or under-saturated. This issue has fundamental implications for determining the long term S budget of the martian surface and atmosphere (from mantle degassing), as well as evolution of the highly siderophile elements (HSE) Au, Pd, Pt, Re, Rh, Ru, Ir, and Os, since concentrations of the latter are controlled by sulfide stability. Resolution of sulfide saturation depends upon temperature, pressure, oxygen fugacity (and FeO), and magma composition [2]. Expressions derived from experimental studies allow prediction of S contents, though so far they are not calibrated for shergottitic liquids [3-5]. We have carried out new experiments designed to test current S saturation models, and then show that existing calibrations are not suitable for high FeO and low Al2O3 compositions characteristic of shergottitic liquids. The new results show that existing models underpredict S contents of sulfide saturated shergottitic liquids by a factor of 2.

  9. New eucrite Dar al Gani 872: Petrography, chemical composition, and evolution

    NASA Astrophysics Data System (ADS)

    Patzer, A.; Hill, D. H.; Boynton, W. V.

    2003-05-01

    Dar al Gani 872 (DaG 872) is a new meteorite from Libya that we classified by means of Instrumental Neutron Activation Analysis (INAA), electron microprobe, and optical microscopy. According to our results, DaG 872 is a Mg-rich main group eucrite, i.e., a monomict noncumulate basaltic eucrite displaying a predominant coarse-grained relict subophitic and a fine-grained granulitic texture. The meteorite also shows pockets of late-stage mesostasis and is penetrated by several calcite veins due to terrestrial weathering. Finally, it exhibits shock phenomena of stage 1­2 including heavily fractured mineral components, undulose extinction of plagioclase, kinked lamellae, and mosaicism in pyroxenes corresponding to peak pressures of ~20 GPa. In view of petrographic criteria as well as compositional and exsolution characteristics of its pyroxenes, the sample represents a metamorphic type 5 eucrite. Assuming the metamorphic type to be a function of burial depth on the parent body and taking into account the relatively high shock stage, the excavation of DaG 872 was likely induced by a major impact event. Prior to this point, DaG 872 apparently underwent a 4-stage geological evolution that is reflected by intricate textural and mineralogical features.

  10. Shergottite Impact Melt Glasses Contain Soil from Martian Uplands

    NASA Technical Reports Server (NTRS)

    Rao, M. N.; McKay, D. S.

    2002-01-01

    Martian meteorite (shergottite) impact melt glasses that contain high concentrations of martian atmospheric noble gases and show significant variations in Sr-87/Sr-86 isotopic ratios are likely to contain Martian surface fines mixed with coarser regolith materials. The mixed soil constituents were molten due to shock at the time of meteoroid impact near the Martian surface and the molten glass got incorporated into the voids and cracks in some shergottite meteorites. Earlier, Rao et al. found large enrichments of sulfur (sulfate) during an electron-microprobe study of several impact melt glass veins and pods in EET79001,LithC thin sections. As sulfur is very abundant in Martian soil, these S excesses were attributed to the mixing of a soil component containing aqueously altered secondary minerals with the LithC precursor materials prior to impact melt generation. Recently, we studied additional impact melt glasses in two basaltic shergottites, Zagami and Shergotty using procedures similar to those described by Rao et al. Significant S enrichments in Zagami and Shergotty impact melt glass veins similar to the EET79001, LithC glasses were found. In addition, we noticed the depletion of the mafic component accompanied by the enrichment of felsic component in these impact melt glass veins relative to the bulk host rock in the shergottites. To explain these observations, we present a model based on comminution of basaltic rocks due to meteroid bombardment on martian regolith and mechanical fractionation leading to enrichment of felsics and depletion of mafics in the fine grained dust which is locally mobilized as a result of saltation and deflation due to the pervasive aeolian activity on Mars.

  11. Shergottite Impact Melt Glasses Contain Soil from Martian Uplands

    NASA Technical Reports Server (NTRS)

    Rao, M. N.; McKay, D. S.

    2002-01-01

    Martian meteorite (shergottite) impact melt glasses that contain high concentrations of martian atmospheric noble gases and show significant variations in Sr-87/Sr-86 isotopic ratios are likely to contain Martian surface fines mixed with coarser regolith materials. The mixed soil constituents were molten due to shock at the time of meteoroid impact near the Martian surface and the molten glass got incorporated into the voids and cracks in some shergottite meteorites. Earlier, Rao et al. found large enrichments of sulfur (sulfate) during an electron-microprobe study of several impact melt glass veins and pods in EET79001,LithC thin sections. As sulfur is very abundant in Martian soil, these S excesses were attributed to the mixing of a soil component containing aqueously altered secondary minerals with the LithC precursor materials prior to impact melt generation. Recently, we studied additional impact melt glasses in two basaltic shergottites, Zagami and Shergotty using procedures similar to those described. Significant S enrichments in Zagami and Shergotty impact melt glass veins similar to the EET79001, LithC glasses were found. In addition, we noticed the depletion of the mafic component accompanied by the enrichment of felsic component in these impact melt glass veins relative to the bulk host rock in the shergottites. To explain these observations, we present a model based on comminution of basaltic rocks due to meteoroid bombardment on martian regolith and mechanical fractionation leading to enrichment of felsics and depletion of mafics in the fine grained dust which is locally mobilized as a result of saltation and deflation due to the pervasive aeolian activity on Mars.

  12. Compositional Controls on the Formation of Kaersutite Amphibole in Shergottite Meteorites

    NASA Technical Reports Server (NTRS)

    Pitman, K. M.; Treiman, A. H.

    2004-01-01

    The shergottite basalts, meteorites of Martian origin, contain rare small grains (approx. 10-100 microns diam.) of kaersutite, a Ca-amphibole rich in Al and Ti. Kaersutites have been used to estimate the water content of shergottites and the Martian mantle; however, questions remain about the original water content of the amphiboles and if they formed from magma. We investigated the petrographic settings of amphiboles in two shergottites and confirm that these amphiboles occur only in multiphase inclusions in pyroxene. In fact, kaersutite is found only in pigeonite. This suggests that the occurrence of amphibole is controlled in part by the composition of its host phase. Crystallization of host (cognate) pigeonite from a magmatic inclusion will enrich the remaining melt in Ca, Al, and Ti, supporting formation of kaersutite.

  13. The source crater of martian shergottite meteorites.

    PubMed

    Werner, Stephanie C; Ody, Anouck; Poulet, François

    2014-03-21

    Absolute ages for planetary surfaces are often inferred by crater densities and only indirectly constrained by the ages of meteorites. We show that the <5 million-year-old and 55-km-wide Mojave Crater on Mars is the ejection source for the meteorites classified as shergottites. Shergottites and this crater are linked by their coinciding meteorite ejection ages and the crater formation age and by mineralogical constraints. Because Mojave formed on 4.3 billion-year-old terrain, the original crystallization ages of shergottites are old, as inferred by Pb-Pb isotope ratios, and the much-quoted shergottite ages of <600 million years are due to resetting. Thus, the cratering-based age determination method for Mars is now calibrated in situ, and it shifts the absolute age of the oldest terrains on Mars backward by 200 million years. PMID:24603150

  14. The Martian Surface is old and so are Shergottites

    NASA Astrophysics Data System (ADS)

    Bouvier, A.; Blichert-Toft, J.; Vervoort, J. D.; Albarede, F.

    2005-12-01

    very old and formed mostly over the first one billion years of the planet's history, thus eliminating the above paradox. We further interpret the young shergottite Rb-Sr, Sm-Nd, and Lu-Hf ages to be the result of the resetting of these isotopic systems by acidic groundwater percolation through the Martian crust, ending approximately 150-300 My ago. We argue that throughout much of Martian history, large acid lakes of regional extent collected and mixed groundwaters and redistributed 142Nd and 182W between rocks of different ages, some of them nearly as old as the planet itself and carrying strong isotopic anomalies. From an interpretation of satellite images, it has been argued (10) that over the planet's first billion years of evolution, one third of its surface was covered by bodies of standing water and ice floodwaters derived from a subpermafrost aquifer. The last pools of liquid water occupying various spots on the Martian surface may have disappeared either by evaporation or by retreating into a permafrost layer now buried beneath thick wind-blown deposits. 1. Chen and Wasserburg, GCA 50, 955 (1986). 2. Nyquist et al., Space Sci. Rev. 96, 105 (2001). 3. Clayton and Mayeda, GCA 60, 1999 (1996). 4. Franchi et al., Phil. Trans. R. Soc. London, 359, 2019 (2001). 5. Squyres et al., Science 306, 1698 (2004). 6. Gendrin et al., Science 307, 1587 (2005). 7. Fairen et al., Nature 431, 423 (2004). 8. McCoy et al., GCA 63, 1249 (1999). 9. Dreibus et al., LPS 27, 323 (1996). 10. Clifford, Icarus 154, 40 (2001).

  15. Martian meteorite Tissint records unique petrogenesis among the depleted shergottites

    NASA Astrophysics Data System (ADS)

    Basu Sarbadhikari, A.; Babu, E. V. S. S. K.; Vijaya Kumar, T.; Chennaoui Aoudjehane, H.

    2016-09-01

    Tissint, a new unaltered piece of Martian volcanic materials, is the most silica-poor and Mg-Fe-rich igneous rock among the "depleted" olivine-phyric shergottites. Fe-Mg zoning of olivine suggests equilibrium growth (<0.1 °C h-1) in the range of Fo80-56 and olivine overgrowth (Fo55-18) through a process of rapid disequilibrium (~1.0-5.0 °C h-1). The spatially extended (up to 600 μm) flat-top Fe-Mg profiles of olivine indicates that the early-stage cooling rate of Tissint was slower than the other shergottites. The chemically metastable outer rim of olivine (shergottites. Dominance of augite over plagioclase induced augite to control the Ca-buffer in the residual melt suppressing the plagioclase crystallization, which also caused a profound effect on the Al-content in the late-crystallized pyroxenes. Mineral chemical stability, phase-assemblage saturation, and pressure-temperature path of evolution indicates that the parent magma entered the solidus and left the liquidus field at a depth of 40-80 km in the upper mantle. Petrogenesis of Tissint appears to be similar to LAR 06319, an enriched olivine-phyric shergottite, during the early to intermediate stage of crystallization. A severe shock-induced deformation resulted in remelting (10-15 vol%), recrystallization (most Fe-rich phases), and exhumation of Tissint in a time scale of 1-8 yr. Tissint possesses some distinct characteristics, e.g., impact-induced melting and deformation, forming phosphorus-rich recrystallization rims of olivine, and shock-induced melt domains without relative enrichment of LREEs compared to the bulk; and shared characteristics, e.g., modal

  16. Martian meteorite Tissint records unique petrogenesis among the depleted shergottites

    NASA Astrophysics Data System (ADS)

    Basu Sarbadhikari, A.; Babu, E. V. S. S. K.; Vijaya Kumar, T.; Chennaoui Aoudjehane, H.

    2016-07-01

    Tissint, a new unaltered piece of Martian volcanic materials, is the most silica-poor and Mg-Fe-rich igneous rock among the "depleted" olivine-phyric shergottites. Fe-Mg zoning of olivine suggests equilibrium growth (<0.1 °C h-1) in the range of Fo80-56 and olivine overgrowth (Fo55-18) through a process of rapid disequilibrium (~1.0-5.0 °C h-1). The spatially extended (up to 600 μm) flat-top Fe-Mg profiles of olivine indicates that the early-stage cooling rate of Tissint was slower than the other shergottites. The chemically metastable outer rim of olivine (shergottites. Dominance of augite over plagioclase induced augite to control the Ca-buffer in the residual melt suppressing the plagioclase crystallization, which also caused a profound effect on the Al-content in the late-crystallized pyroxenes. Mineral chemical stability, phase-assemblage saturation, and pressure-temperature path of evolution indicates that the parent magma entered the solidus and left the liquidus field at a depth of 40-80 km in the upper mantle. Petrogenesis of Tissint appears to be similar to LAR 06319, an enriched olivine-phyric shergottite, during the early to intermediate stage of crystallization. A severe shock-induced deformation resulted in remelting (10-15 vol%), recrystallization (most Fe-rich phases), and exhumation of Tissint in a time scale of 1-8 yr. Tissint possesses some distinct characteristics, e.g., impact-induced melting and deformation, forming phosphorus-rich recrystallization rims of olivine, and shock-induced melt domains without relative enrichment of LREEs compared to the bulk; and shared characteristics, e.g., modal

  17. Petrology and Geochemistry of a Mg- and Al-Rich Orthopyroxenite Xenolith in the EETA79001 Shergottite: Implications for Mars Crustal Evolution

    NASA Technical Reports Server (NTRS)

    Berkley, John L.

    1999-01-01

    EETA79001 is a Mars meteorite (SNC) consisting of multiple rock types, including two basalt types, olivine and pyroxene xenocrysts, and ultramafic xenoliths. This study is focused on the petrology and geochemistry of one orthopyroxenite xenolith in PTS 68, designated X-1. It consists of chemically homogeneous orthopyroxene cores with exceptionally high Mg/Fe (mg#=85) and Al. Cores are permeated by minute high-Si+Al glassy inclusions, some with augite microlites. Magnesian core areas are mantled by more Fe-rich orthopyroxene rims grading to pigeonite away from cores. The xenolith is transected by cross-cutting shear planes, some of pre-incorporation origin. Major and minor element composition and variation suggest that core areas are primarily igneous, crystallized from a high temperature mafic melt. However, nearly constant mg# across cores suggest metamorphic equilibration. Si+Al inclusions may result from, among other processes, exsolution of feldspathic material during subsolidus cooling, or may be solid materials (alkali feldspar) poikilitically enclosed by growing igneous orthopyroxene crystals. Late reaction with more fractionated melts produced Fe-rich mantles, the whole assemblage later cut by tectonic micro-shear planes. Raw electron microprobe data produced during this study are available on request from the author.

  18. The age of the martian meteorite Northwest Africa 1195 and the differentiation history of the shergottites

    SciTech Connect

    Symes, S; Borg, L; Shearer, C; Irving, A

    2007-04-05

    Samarium-neodymium isotopic analyses of unleached and acid-leached mineral fractions from the recently identified olivine-bearing shergottite Northwest Africa 1195 yield a crystallization age of 348 {+-} 19 Ma and an {var_epsilon}{sub Nd}{sup 143} value of +40.1 {+-} 1.3. Maskelynite fractions do not lie on the Sm-Nd isochron and appear to contain a martian surface component with low {sup 147}Sm/{sup 144}Nd and {sup 143}Nd/{sup 144}Nd ratios that was added during shock. The Rb-Sr system is disturbed and does not yield an isochron. Terrestrial Sr appears to have affected all of the mineral fractions, although a maximum initial {sup 87}Sr/{sup 86}Sr ratio of 0.701614 {+-} 16 is estimated by passing a 348 Ma reference isochron through the maskelynite fraction that is least affected by contamination. The high initial {var_epsilon}{sub Nd}{sup 143} value and the low initial {sup 87}Sr/{sup 86}Sr ratio, combined with the geologically young crystallization age, indicate that Northwest Africa 1195 is derived from a source region characterized by a long-term incompatible element depletion. The age and initial Sr and Nd isotopic compositions of Northwest Africa 1195 are very similar to those of Queen Alexandra Range 94201, indicating these samples were derived from source regions with nearly identical Sr-Nd isotopic systematics. These similarities suggest that these two meteorites share a close petrogenetic relationship and might have been erupted from a common volcano. The meteorites Yamato 980459, Dar al Gani 476, Sayh al Uhaymir 005/008, and Dhofar 019 also have relatively old ages between 474-575 Ma and trace element and/or isotopic systematics that are indicative of derivation from incompatible-element-depleted sources. This suggests that the oldest group of meteorites is more closely related to one another than they are to the younger meteorites that are derived from less incompatible-element-depleted sources. Closed-system fractional crystallization of this suite of

  19. An Exploration of the Viability of Partnership between "Dar Al-Ulum" and Higher Education Institutions in North West England Focusing upon Pedagogy and Relevance

    ERIC Educational Resources Information Center

    Geaves, Ron

    2015-01-01

    The article explores possibilities of collaboration between Muslim providers of traditional education ("dar al-ulums") and HE/FE institutions in close geographical proximity in the North West England. It reports the outcomes of a project carried out in 2011/2012 influenced by the findings of the Makadam/Scott-Baumann report in 2010, in…

  20. Solar proton produced neon in shergottite meteorites

    NASA Technical Reports Server (NTRS)

    Garrison, D. H.; Rao, M. N.; Bogard, D. D.

    1994-01-01

    Cosmogenic radionuclides produced by near-surface, nuclear interactions of energetic solar protons (approx. 10-100 MeV) were reported in several lunar rocks and a very small meteorites. We recently documented the existence and isotopic compositions of solar-produced (SCR) Ne in two lunar rocks. Here we present the first documented evidence for SCR Ne in a meteorite, ALH77005, which was reported to contain SCR radionuclides. Examination of literature data for other shergottites suggests that they may also contain a SCR Ne component. The existence of SCR Ne in shergottites may be related to a Martian origin.

  1. Sulfur Isotopes in Gas-rich Impact-Melt Glasses in Shergottites

    NASA Technical Reports Server (NTRS)

    Rao, M. N.; Hoppe, P.; Sutton, S. R.; Nyquist, Laurence E.; Huth, J.

    2010-01-01

    Large impact melt glasses in some shergottites contain huge amounts of Martian atmospheric gases and they are known as gas-rich impact-melt (GRIM) glasses. By studying the neutron-induced isotopic deficits and excesses in Sm-149 and Sm-150 isotopes resulting from Sm-149 (n,gamma) 150Sm reaction and 80Kr excesses produced by Br-79 (n,gamma) Kr-80 reaction in the GRIM glasses using mass-spectrometric techniques, it was shown that these glasses in shergottites EET79001 and Shergotty contain regolith materials irradiated by a thermal neutron fluence of approx.10(exp 15) n/sq cm near Martian surface. Also, it was shown that these glasses contain varying amounts of sulfates and sulfides based on the release patterns of SO2 (sulfate) and H2S (sulfide) using stepwise-heating mass-spectrometric techniques. Furthermore, EMPA and FE-SEM studies in basaltic-shergottite GRIM glasses EET79001, LithB (,507& ,69), Shergotty (DBS I &II), Zagami (,992 & ,994) showed positive correlation between FeO and "SO3" (sulfide + sulfate), whereas those belonging to olivine-phyric shergottites EET79001, LithA (,506, & ,77) showed positive correlation between CaO/Al2O3 and "SO3".

  2. Basaltic Shergottite NWA 856: Differentiation of a Martian Magma

    NASA Technical Reports Server (NTRS)

    Ferdous, J.; Brandon, A. D.; Peslier, A. H.; Pirotte, Z.

    2016-01-01

    NWA 856 or Djel Ibone, is a basaltic shergottite discovered as a single stone of 320 g in South Morocco in April, 2001. This meteorite is fresh, i.e. shows minimal terrestrial weathering for a desert find. No shergottite discovered in North Africa can be paired with NWA 856. The purpose of this study is to constrain its crystallization history using textural observations, crystallization sequence modeling and in-situ trace element analysis in order to understand differentiation in shergottite magmatic systems.

  3. Shock Metamorphism of the Dhofar 378 Basaltic Shergottite

    NASA Technical Reports Server (NTRS)

    Mikouchi, T.; McKay, G.

    2006-01-01

    Shock metamorphism is one of the most fundamental processes in the history of Martian meteorites, especially shergottites, which affect their mineralogy and chronology. The formation of "maskelynite" from plagioclase and shock melts is such major mineralogical effects. Dhofar 378 is one of the recently found desert shergottites that is mainly composed of plagioclase and pyroxene. This shergottite is important because of its highly shocked nature and unique plagioclase texture, and thus has a great potential for assessing a "shock" age of shergottites. We have been working on a combined study of mineralogy and chronology of the same rock chip of Dhofar 378. This abstract reports its mineralogical part.

  4. A More Reduced Mantle Source for Enriched Shergottites; Insights from the Olivine-Phyric Shergottite Lar 06319

    NASA Technical Reports Server (NTRS)

    Peslier, A. H.; Hnatyshin, D.; Herd, C. D. K.; Walton, E. L.; Brandon, A. D.; Lapen, T. J.; Shafer, J.

    2010-01-01

    A detailed petrographic study of melt inclusions and Cr-Fe-Ti oxides of LAR 06319 leads to two main conclusions: 1) this enriched oxidized olivine- phyric shergottite represents nearly continuous crystallization of a basaltic shergottite melt, 2) the melt became more oxidized during differentiation. The first crystallized mineral assemblages record the oxygen fugacity which is closest to that of the melt s mantle source, and which is lower than generally attributed to the enriched shergottite group.

  5. Northwest Africa 5298: A Basaltic Shergottite

    NASA Technical Reports Server (NTRS)

    Hui, Hejiu; Peslier, Anne; Lapen, Thomas J.; Brandon, Alan; Shafer, John

    2009-01-01

    NWA 5298 is a single 445 g meteorite found near Bir Gandouz, Morocco in March 2008 [1]. This rock has a brown exterior weathered surface instead of a fusion crust and the interior is composed of green mineral grains with interstitial dark patches containing small vesicles and shock melts [1]. This meteorite is classified as a basaltic shergottite [2]. A petrologic study of this Martian meteorite is being carried out with electron microprobe analysis and soon trace element analyses by laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS). Oxygen fugacity is calculated from Fe-Ti oxides pairs in the sample. The data from this study constrains the petrogenesis of basaltic shergottites.

  6. Volatile compounds in shergottite and nakhlite meteorites

    NASA Technical Reports Server (NTRS)

    Gooding, James L.; Aggrey, Kwesi E.; Muenow, David W.

    1990-01-01

    Since discovery of apparent carbonate carbon in Nakhla, significant evidence has accumulated for occurrence of volatile compounds in shergotties and nakhlites. Results are presented from a study of volatile compounds in three shergottites, one nakhlite, and three eucrite control samples. Shergotties ALHA77005, EETA79001, and Shergotty, and the nakhlite Nakhla, all contain oxidized sulfur (sulfate) of preterrestrial origin; sulfur oxidation is most complete in EETA79001/Lith-C. Significant bulk carbonate was confirmed in Nakhla and trace carbonate was substantiated for EETA79001, all of which appears to be preterrestrial in origin. Chlorine covaries with oxidized sulfur, whereas carbonate and sulfate are inversely related. These volatile compounds were probably formed in a highly oxidizing, aqueous environment sometime in the late stage histories of the rocks that are now represented as meteorites. They are consistent with the hypothesis that shergottite and nakhlite meteorites originated on Mars and that Mars has supported aqueous geochemistry during its history.

  7. Uls LiDAR Supported Analyses of Laser Beam Penetration from Different ALS Systems Into Vegetation

    NASA Astrophysics Data System (ADS)

    Wieser, M.; Hollaus, M.; Mandlburger, G.; Glira, P.; Pfeifer, N.

    2016-06-01

    This study analyses the underestimation of tree and shrub heights for different airborne laser scanner systems and point cloud distribution within the vegetation column. Reference data was produced by a novel UAV-borne laser scanning (ULS) with a high point density in the complete vegetation column. With its physical parameters (e.g. footprint) and its relative accuracy within the block as stated in Section 2.2 the reference data is supposed to be highly suitable to detect the highest point of the vegetation. An airborne topographic (ALS) and topo-bathymetric (ALB) system were investigated. All data was collected in a period of one month in leaf-off condition, while the dominant tree species in the study area are deciduous trees. By robustly estimating the highest 3d vegetation point of each laser system the underestimation of the vegetation height was examined in respect to the ULS reference data. This resulted in a higher under-estimation of the airborne topographic system with 0.60 m (trees) and 0.55 m (shrubs) than for the topo-bathymetric system 0.30 m (trees) and 0.40 m (shrubs). The degree of the underestimation depends on structural characteristics of the vegetation itself and physical specification of the laser system.

  8. The case for old basaltic shergottites

    NASA Astrophysics Data System (ADS)

    Bouvier, Audrey; Blichert-Toft, Janne; Vervoort, Jeffrey D.; Gillet, Philippe; Albarède, Francis

    2008-02-01

    The crystallization age of shergottites is currently not agreed upon. Although mineral 87Rb- 87Sr, 147Sm- 143Nd, 176Lu- 176Hf, and U-Pb isochrons all give very young ages, typically in the range of 160-180 Ma, 207Pb- 206Pb data support a much older crystallization age at 4.1 Ga, which is consistent with published whole-rock 87Rb- 87Sr data on basaltic shergottites. Different isotopic systems present different complexities, but crater-counting chronology, which shows that a substantial fraction of the Martian surface was resurfaced during the late heavy bombardment, is in favor of an old Martian lithosphere with ages in accordance with Pb-Pb and Rb-Sr isotopic data. A ˜ 4.1 Ga Pb-Pb age of shergottites also agrees with the 142Nd and 182W anomalies found in these rocks and concur with the presence of an actively convecting mantle during the first 500 Myr of the planet's history. We here present new Sm-Nd, Lu-Hf, and Pb-Pb mineral isochrons for the basaltic shergottites Shergotty and Los Angeles complementing our previous results on Zagami [Bouvier A., Blichert-Toft J., Vervoort J.D. and Albarède F. (2005). The age of SNC meteorites and the antiquity of the Martian surface, Earth Planet. Sci. Lett. 240, 221-233]. The internal 147Sm- 143Nd and 176Lu- 176Hf isochrons give young ages of, respectively, 172 ± 40 (MSWD = 2.0) and 188 ± 91 (MSWD = 3.1) for Shergotty, and 181 ± 13 (MSWD = 0.14) and 159 ± 42 (MSWD = 0.01) for Los Angeles. In contrast, the Pb isotope compositions of the leached whole-rock fragments and maskelynite separates of Shergotty and Los Angeles fall on the whole-rock isochron previously established for Zagami and other shergottite samples and collectively yield a Pb-Pb age of 4050 ± 70 Ma for the crystallization of the basaltic shergottite suite. The contrast between the ˜ 170 Ma ages of internal isochrons and the 4.1 Ga age supported by Pb-Pb and 87Rb- 87Sr on whole-rocks simply reflects that the younger age dates the perturbation of a suite of

  9. Xenoliths in the EETA 79001 Shergottite: Geological and Astronomical Implications of Similarities to the ALHA 77005 and LEW 88516 Shergottites

    NASA Astrophysics Data System (ADS)

    Treiman, A. H.

    1993-07-01

    79001 basalts, the age 173 +- 10 (2sigms) m.y. [10,5]. Re-examination of shergottite radio-chronologies might resolve this uncertainty. If ALHA77005, the EETA79001 xenoliths, and LEW88516 are closely related, it is likely that they came from the same region on their parent planet (Mars), and so were probably ejected into space by a single impact event. In this case, the 0.6-m.y. cosmic ray exposure age of EETA79001 must date an impact in space, as the cosmic ray exposure ages for ALHA77005 and LEW88516 are ~2.8 m.y. [12,13]. References: [1] Steele I. M. and Smith J. V. (1982) Proc. LPSC 13th, in JGR, 87, A375-A384. [2] McSween H. Y. Jr. and Jarosewich E. (1983) GCA, 47, 1501- 1513. [3] McSween H. Y. Jr. et al. (1979) Science, 204, 1201-1203. [4] Harvey R. P. et al. (1993) GCA, in press. [5] Jones J. H. (1986) GCA, 50, 969-977. [6] Shih C.-Y. et al. (1982) GCA, 46, 2323-2344. [7] Jagoutz E. (1989) GCA, 53, 2429-2441. [8] Ostertag R. et al. (1984) EPSL, 67, 162-166. [9] Keller L. P. and Treiman A. H. (1992) Meteoritics, 27, 242. [10] Wooden J. et al. (1982) LPSC XIII, 879-880. [11] Shih C.-Y. et al. (1982) GCA, 46, 2323-2344. [12] Bogard D. D. et al. (1984) GCA, 48, 1723. [13] Bogard D. D. and Garrison D. H. (1993) LPSC XXIV, 139-140.

  10. Chemical Composition of Four Shergottites from Northwest Africa (NWA 2800, NWA, 5214, NWA 5990, NWA 6342)

    NASA Technical Reports Server (NTRS)

    Yang, S.; Humayun, M.; Jefferson, G.; Fields, D.; Righter, K.; Irving, A. J.

    2013-01-01

    Shergottites represent the majority of recovered Martian meteorites. As basic igneous rocks, they formed from magmas that were emplaced in the Martian crust [1]. Due to the low ambient pressure of the Martian atmosphere, subaerial lavas and shallow magma chambers are expected to outgas volatile metals (e.g., Cd, Te, Re, Bi) [2]. The planetary abundances of the volatile siderophile and chalcophile elements are important at establishing the depth of core formation for Mars, and must be known as a baseline for understanding volcanic outgassing on Mars, particularly the large enrichments of S and Cl observed in modern Martian soils [3]. There is little data on volatile siderophile and chalcophile elements from Martian meteorites, excluding a few well-analyzed samples [2]. Further, a large number of shergottites being recovered from North West Africa are in need of chemical analysis. All of the shergottites are in need of state-of-the art analysis for such ratios as Ge/Si and Ga/Al, which can now be accomplished by LA-ICP-MS [2].

  11. Two-stage polybaric formation of the new enriched, pyroxene-oikocrystic, lherzolitic shergottite, NWA 7397

    NASA Astrophysics Data System (ADS)

    Howarth, Geoffrey H.; Pernet-Fisher, John F.; Balta, J. Brian; Barry, Peter H.; Bodnar, Robert J.; Taylor, Lawrence A.

    2014-10-01

    Northwest Africa (NWA) 7397 is a newly discovered, enriched, lherzolitic shergottite, the third described example of this group. This meteorite consists of two distinct textural lithologies (1) poikilitic—comprised of zoned pyroxene oikocrysts, with chadacrysts of chromite and olivine, and (2) nonpoikilitic—comprised of olivine, low-Ca and high-Ca pyroxene, maskelynite, and minor abundances of merrillite, spinel, ilmenite, and pyrrhotite. The constant Ti/Al ratios of pyroxene oikocrysts suggests initial crystallization of the poikilitic lithology at depth (equivalent to pressures of approximately 10 kbar), followed by crystallization of the nonpoikilitic lithology at shallower levels. Oxygen fugacity conditions become more oxidizing during crystallization ranging from fO2 conditions of approximately QFM-2 to QFM-0.7. Magma calculated to be in equilibrium with the major rock-forming minerals is LREE-enriched relative to depleted or intermediate shergottites and has flat overall profiles. Therefore, we suggest that the parental magma for NWA 7397 had sampled an enriched, oxidized, Martian geochemical source, similar to that of other enriched basaltic and olivine-phyric shergottites. We present a polybaric formation model for the lherzolitic shergottite NWA 7397, to account for the petrologic constraints. Three successive stages in the development of NWA 7397 are discussed (1) formation of a REE-enriched parental magma from a distinct Martian mantle reservoir; (2) magma ponding and development of a staging chamber concomitant with initial crystallization of the poikilitic lithology; and (3) magma ascent to the near surface, with entrainment of cumulates from the staging chamber and subsequent crystallization of the nonpoikilitic lithology en route to the surface.

  12. Geochemistry of Intermediate Olivine-Phyric Shergottite Northwest Africa 6234

    NASA Astrophysics Data System (ADS)

    Filiberto, J.; Chin, E.; Day, J. M. D.; Gross, J.; Penniston-Dorland, S. C.; Schwenzer, S. P.; Treiman, A. H.

    2012-03-01

    Here we present major- and trace-element geochemistry, Li-isotope composition and abundance, and Re-Os isotope and highly siderophile element abundance data for the ol-phyric shergottite Northwest Africa 6234.

  13. Terrestrial C-14 age of the Antarctic shergottite, EETA 79001

    NASA Technical Reports Server (NTRS)

    Jull, A. J. T.; Donahue, D. J.

    1988-01-01

    The terrestrial age of the Elephant Moraine shergottite EETA 79001 (lithology A) has been determined from measurement of its cosmogenic C-14 content as 12 +/- 2 kyr. The results on saturated and blank samples of 1 g or less are also discussed. The age calculated for EETA 79001 is compared to exposure and terrestrial ages of other shergottites in the light of possible origins of these meteorites on Mars.

  14. Petrology and chemistry of the basaltic shergottite North West Africa 480

    NASA Astrophysics Data System (ADS)

    Barrat, J. A.; Gillet, Ph.; Sautter, V.; Jambon, A.; Javoy, M.; Göpel, C.; Lesourd, M.; Keller, F.; Petit, E.

    2002-04-01

    North West Africa (NWA) 480 is a new martian meteorite of 28 g found in the Moroccan Sahara in November 2000. It consists mainly of large gray pyroxene crystals (the largest grains are up to 5 mm in length) and plagioclase converted to maskelynite. Excluding the melt pocket areas, modal analyses indicate the following mineral proportions: 72 vol% pyroxenes extensively zoned, 25% maskelynite, 1% phosphates (merrillite and chlorapatite), 1% opaque oxides (ilmenite, ulvospinel and chromite) and sulfides, and 1% others such as silica and fayalite. The compositional trend of NWA 480 pyroxenes is similar to that of Queen Alexandra Range (QUE) 94201 but in NWA 480 the pyroxene cores are more Mg-rich (En77-En65). Maskelynites display a limited zoning (An42-50Ab54-48Or2-4). Our observations suggest that NWA 480 formed from a melt with a low nuclei density at a slow cooling rate. The texture was achieved via a single-stage cooling where pyroxenes grew continuously. A similar model was previously proposed for QUE 94201 by McSween et al. (1996). NWA 480 is an Al-poor ferroan basaltic rock and resembles Zagami or Shergotty for major elements and compatible trace element abundances. The bulk rock analysis for oxygen isotopes yields V17O = +0.42%o, a value in agreement at the high margin, with those measured on other shergottites (Clayton and Mayeda, 1996; Romanek et al., 1998; Franchi et al., 1999). Its CI-normalized rare earth element pattern is similar to those of peridotitic shergottites such as Allan Hills (ALH)A77005, suggesting that these shergottites shared a similar parent liquid, or at least the same mantle source.

  15. Complex Formation History of Highly Evolved Basaltic Shergottite, Zagami

    NASA Technical Reports Server (NTRS)

    Niihara, T.; Misawa, K.; Mikouchi, T.; Nyquist, L. E.; Park, J.; Hirata, D.

    2012-01-01

    Zagami, a basaltic shergottite, contains several kinds of lithologies such as Normal Zagami consisting of Fine-grained (FG) and Coarse-grained (CG), Dark Mottled lithology (DML), and Olivine-rich late-stage melt pocket (DN). Treiman and Sutton concluded that Zagami (Normal Zagami) is a fractional crystallization product from a single magma. It has been suggested that there were two igneous stages (deep magma chamber and shallow magma chamber or surface lava flow) on the basis of chemical zoning features of pyroxenes which have homogeneous Mg-rich cores and FeO, CaO zoning at the rims. Nyquist et al. reported that FG has a different initial Sr isotopic ratio than CG and DML, and suggested the possibility of magma mixing on Mars. Here we report new results of petrology and mineralogy for DML and the Olivine-rich lithology (we do not use DN here), the most evolved lithology in this rock, to understand the relationship among lithologies and reveal Zagami s formation history

  16. Crystallization Age of NWA 1460 Shergottite: Paradox Revisited

    NASA Technical Reports Server (NTRS)

    Nyquist, L. E.; Shih, C-Y.; Reese, Y. D.; Irving, A. J.

    2004-01-01

    We have determined the Rb-Sr age of basaltic shergottite NWA 1460 to be 312 +/- 3 Ma, and the Sm-Nd age to be 352 +/- 30 Ma. The initial Sr and Nd isotopic compositions of NWA 1460 suggest it is an earlier melting product of a Martian mantle source region similar to those of the Iherzolitic shergottites and basaltic shergottite EETA79001, lithology B. The new ages of NWA 1460 and other recently analyzed Martian meteorites leads us to reexamine the paradox that most of the Martian meteorites appear to be younger from the majority of the Martian surface. This paradox continues to pose a challenge to determining a reliable Martian chronology.

  17. Acid-Sulfate-Weathering Activity in Shergottite Sites on Mars Recorded in Grim Glasses

    NASA Technical Reports Server (NTRS)

    Rao, M. N.; Nyquist, L. E.; Ross, K.; Sutton, S. R.; Schwandt, C. S.

    2011-01-01

    Based on mass spectrometric studies of sulfur species in Shergotty and EET79001, [1] and [2] showed that sulfates and sulfides occur in different proportions in shergottites. Sulfur speciation studies in gas-rich impact-melt (GRIM) glasses in EET79001 by the XANES method [3] showed that S K-XANES spectra in GRIM glasses from Lith A indicate that S is associated with Ca and Al presumably as sulfides/sulfates whereas the XANES spectra of amorphous sulfide globules in GRIM glasses from Lith B indicate that S is associated with Fe as FeS. In these amorphous iron sulfide globules, [4] found no Ni using FE-SEM and suggested that the globules resulting from immiscible sulfide melt may not be related to the igneous iron sulfides having approximately 1-3% Ni. Furthermore, in the amorphous iron sulfides from 507 GRIM glass, [5] determined delta(sup 34)S values ranging from +3.5%o to -3.1%o using Nano-SIMS. These values plot between the delta(sup 34)S value of +5.25%o determined in the sulfate fraction in Shergotty [6] at one extreme and the value of -1.7%o obtained for igneous sulfides in EET79001 and Shergotty [7] at the other. These results suggest that the amorphous Fe-S globules likely originated by shock reduction of secondary iron sulfate phases occurring in the regolith precursor materials during impact [7]. Sulfates in the regolith materials near the basaltic shergottite sites on Mars owe their origin to surficial acid-sulfate interactions. We examine the nature of these reactions by studying the composition of the end products in altered regolith materials. For the parent material composition, we use that of the host shergottite material in which the impact glasses are situated.

  18. Partitioning of light lithophile elements during basalt eruptions on Earth and application to Martian shergottites

    NASA Astrophysics Data System (ADS)

    Edmonds, Marie

    2015-02-01

    An enigmatic record of light lithophile element (LLE) zoning in pyroxenes in basaltic shergottite meteorites, whereby LLE concentrations decrease dramatically from the cores to the rims, has been interpreted as being due to partitioning of LLE into a hydrous vapor during magma ascent to the surface on Mars. These trends are used as evidence that Martian basaltic melts are water-rich (McSween et al., 2001). Lithium and boron are light lithophile elements (LLE) that partition into volcanic minerals and into vapor from silicate melts, making them potential tracers of degassing processes during magma ascent to the surface of Earth and of other planets. While LLE degassing behavior is relatively well understood for silica-rich melts, where water and LLE concentrations are relatively high, very little data exists for LLE abundance, heterogeneity and degassing in basaltic melts. The lack of data hampers interpretation of the trends in the shergottite meteorites. Through a geochemical study of LLE, volatile and trace elements in olivine-hosted melt inclusions from Kilauea Volcano, Hawaii, it can be demonstrated that lithium behaves similarly to the light to middle rare Earth elements during melting, magma mixing and fractionation. Considerable heterogeneity in lithium and boron is inherited from mantle-derived primary melts, which is dominant over the fractionation and degassing signal. Lithium and boron are only very weakly volatile in basaltic melt erupted from Kilauea Volcano, with vapor-melt partition coefficients <0.1. Degassing of LLE is further inhibited at high temperatures. Pyroxene and associated melt inclusion LLE concentrations from a range of volcanoes are used to quantify lithium pyroxene-melt partition coefficients, which correlate negatively with melt H2O content, ranging from 0.13 at low water contents to <0.08 at H2O contents >4 wt%. The observed terrestrial LLE partitioning behavior is extrapolated to Martian primitive melts through modeling. The zoning

  19. Lead Isotopes in Olivine-Phyric Shergottite Tissint: Implications for the Geochemical Evolution of the Shergottite Source Mantle

    NASA Technical Reports Server (NTRS)

    Moriwaki, R.; Usui, T.; Simon, J. I.; Jones, J. H.; Yokoyama, T.

    2015-01-01

    Geochemically-depleted shergottites are basaltic rocks derived from a martian mantle source reservoir. Geochemical evolution of the martian mantle has been investigated mainly based on the Rb-Sr, Sm-Nd, and Lu-Hf isotope systematics of the shergottites [1]. Although potentially informative, U-Th- Pb isotope systematics have been limited because of difficulties in interpreting the analyses of depleted meteorite samples that are more susceptible to the effects of near-surface processes and terrestrial contamination. This study conducts a 5-step sequential acid leaching experiment of the first witnessed fall of the geochemically-depleted olivinephyric shergottite Tissint to minimize the effect of low temperature distrubence. Trace element analyses of the Tissint acid residue (mostly pyroxene) indicate that Pb isotope compositions of the residue do not contain either a martian surface or terrestrial component, but represent the Tissint magma source [2]. The residue has relatively unradiogenic initial Pb isotopic compositions (e.g., 206Pb/204Pb = 10.8136) that fall within the Pb isotope space of other geochemically-depleted shergottites. An initial µ-value (238U/204Pb = 1.5) of Tissint at the time of crystallization (472 Ma [3]) is similar to a time-integrated mu- value (1.72 at 472 Ma) of the Tissint source mantle calculated based on the two-stage mantle evolution model [1]. On the other hand, the other geochemically-depleted shergottites (e.g., QUE 94201 [4]) have initial µ-values of their parental magmas distinctly lower than those of their modeled source mantle. These results suggest that only Tissint potentially reflects the geochemical signature of the shergottite mantle source that originated from cumulates of the martian magma ocean

  20. Chemical compositions of martian basalts (shergottites): Some inferences on basalt formation, mantle metasomatism, and differentiation on Mars

    NASA Astrophysics Data System (ADS)

    Treiman, A. H.

    2003-12-01

    Bulk chemical compositions of the shergottite basalts provide important constraints on magma genesis and mantle processes in Mars. Abundances of many major and trace elements in the shergottites covary in 2 distinct groups: Group 1 (G1) includes mostly highly incompatible elements (e.g., La, Th), and Group 2 (G2) includes mostly moderately incompatible elements (e.g., Ti, Lu, Al, Hf). Covariations of G2 elements (not necessarily linear) are consistent with partitioning between basalt magma and orthopyroxene + olivine. This fractionation represents partial melting to form the shergottites and their crystallization; the restite minerals cannot include aluminous phase(s), phosphate, ilmenite, zircon, or sulfides. Overall, abundances of G1 elements are decoupled from those of G2. In graphing abundances of a G1 element against those of a G2 element, G1/G2 abundance ratios do not appear to be random but are restricted to 4 values. Shergottites with a given G1/G2 value need not have the same crystallization age and need not fall on a single fractionation trajectory involving compatible elements (e.g., Ti versus Fe*). These observations imply that the G1/G2 families were established before basalt formation and suggest metasomatic enrichment of their source region (major carrier of G2 elements) by a component rich in G1 elements. Group 1 elements were efficiently separated from G2 elements very early in Mars' history. Such efficient fractionation is not consistent with simple petrogenesis; it requires multiple fractionations, "complex" petrogenetic processes, or minerals with unusual geochemistry. The behavior of phosphorus in this early fractionation event is inexplicable by normal petrogenetic processes and minerals. Several explanations are possible, including significant compatibility of P in majoritic garnet and the presence of P-bearing iron metal (or a phosphide phase) in the residual solid assemblage (carrier of G2 elements). If the latter, Mars' mantle is more

  1. Provenance and Concentration of Water in the Shergottite Mantle

    NASA Technical Reports Server (NTRS)

    Jones, J. H.; Usui, T.; Alexander, C. M. O'D.; Simon, J. I.; Wang, J.

    2012-01-01

    The water content of the martian mantle is controversial. In particular, the role of water in the petrogenesis of the shergottites has been much debated. Although the shergottites, collectively, contain very little water [e.g., 1,2], some experiments have been interpreted to show that percent levels of water are required for the petrogenesis of shergottites such as Shergotty and Zagami [3]. In this latter interpretation, the general paucity of water in the shergottites and their constituent minerals is attributed to late-stage degassing. Y980459 (Y98) is a very primitive, perhaps even parental, martian basalt, with a one-bar liquidus temperature of approx.1400 C. Olivine is the liquidus phase, and olivine core compositions are in equilibrium with the bulk rock [e.g., 4]. Petrogenetically, therefore, Y98 has had a rather simple history and can potentially help constrain the role of water in martian igneous processes. In particular, once trapped, melt inclusions should not be affected by subsequent degassing.

  2. Rb-Sr and Sm-Nd Studies of Olivine-Phyric Shergottites RBT 04262 and LAR 06319: Isotopic Evidence for Relationship to Enriched Basaltic Shergottites

    NASA Technical Reports Server (NTRS)

    Nyquist, L.E.; Shih, C.-Y.; Reese, Y.

    2009-01-01

    RBT 04262 and LAR 06319 are two Martian meteorites recently discovered in Antarctica. Both contain abundant olivines, and were classified as olivine-phyric shergottites. A detailed petrographic study of RBT 04262 suggested it should be reclassified as a lherzolitic shergottite. However, the moderately LREE-depleted REE distribution pattern indicated that it is closely related to enriched basaltic shergottites like Shergotty, Zagami, Los Angeles, etc. In earlier studies of a similarly olivinephyric shergottite NWA 1068 which contains 21% modal olivine, it was shown that it probably was produced from an enriched basaltic shergottite magma by olivine accumulation . As for LAR 06319, recent petrographic studies suggested that it is different from either lherzolitic shergottites or the highly LREE-depleted olivine-phyric shergottites. We performed Rb-Sr and Sm-Nd isotopic analyses on RBT 04262 and LAR 06319 to determine their crystallization ages and Sr and Nd isotopic signatures, and to better understand the petrogenetic relationships between them and other basaltic, lherzolitic and depleted olivine-phyric shergottites.

  3. Spinels and oxygen fugacity in olivine-phyric and lherzolitic shergottites

    NASA Astrophysics Data System (ADS)

    Goodrich, C. A.; Herd, C. D. K.; Taylor, L. A.

    2003-12-01

    We examine the occurrences, textures, and compositional patterns of spinels in the olivine- phyric shergottites Sayh al Uhaymir (SaU) 005, lithology A of Elephant Moraine A79001 (EET-A), Dhofar 019, and Northwest Africa (NWA) 1110, as well as the lherzolitic shergottite Allan Hills (ALH) A77005, in order to identify spinel-olivine-pyroxene assemblages for the determination of oxygen fugacity (using the oxybarometer of Wood [1991]) at several stages of crystallization. In all of these basaltic martian rocks, chromite was the earliest phase and crystallized along a trend of strict Cr-Al variation. Spinel (chromite) crystallization was terminated by the appearance of pyroxene but resumed later with the appearance of ulvospinel. Ulvospinel formed overgrowths on early chromites (except those shielded as inclusions in olivine or pyroxene), retaining the evidence of the spinel stability gap in the form of a sharp core/rim boundary (except in ALH A77005, where subsolidus reequilibration diffused this boundary). Secondary effects seen in chromites include reaction with melt before ulvospinel overgrowth, reaction with melt inclusions, reaction with olivine hosts (in ALH A77005), and exsolution of ulvospinel or ilmenite. All chromites experienced subsolidus Fe/Mg reequilibration. Spinel-olivine-pyroxene assemblages representing the earliest stages of crystallization in each rock essentially consist of the highest-Cr#, lowest-fe# chromites not showing secondary effects plus the most magnesian olivine and equilibrium low-Ca pyroxene. Assemblages representing the onset of ulvospinel crystallization consist of the lowest-Ti ulvospinel, the most magnesian olivine in which ulvospinel occurs as inclusions, and equilibrium low-Ca pyroxene. The results show that, for early crystallization conditions, oxygen fugacity (fO2) increases from SaU 005 and Dhofar 019 (~QFM -3.8), to EET-A (QFM -2.8) and ALH A77005 (QFM -2.6), to NWA 1110 (QFM -1.7). Estimates for later conditions indicate

  4. An Experimental Investigation of the Shergottite NWA 6162

    NASA Technical Reports Server (NTRS)

    Barnett, R. Gaylen; Jones, John H.; Draper, David S.; Le, Loan H.

    2012-01-01

    The Martian meteorite North West Africa 6162 (NWA 6162) is a shergottite found in Morocco in 2010. The meteorite has large olivine crystals with Mg-depleted rims as low as FO(sub 65) and Mg-rich cores of up to FO(sub 74). It is similar both in appearance and composition to another shergottite, SaU 005. Our objective is to determine if NWA 6162 represents a liquid or if it is a product of olivine accumulation. Olivine accumulation would leave the parent melt Mg-depleted and the complementary olivine cumulates would be Mg-enriched. Therefore, if NWA 6162 is a partial cumulate we would expect that liquidus olivines grown from this bulk composition would be more magnesium than olivines in the natural sample.

  5. AR-39-AR-40 "Age" of Basaltic Shergottite NWA-3171

    NASA Technical Reports Server (NTRS)

    Bogard, Donald D.; Park, Jisun

    2007-01-01

    North-West-Africa 3171 is a 506 g, relatively fresh appearing, basaltic shergottite with similarities to Zagami and Shergotty, but not obviously paired with any of the other known African basaltic shergottites. Its exposure age has the range of 2.5-3.1 Myr , similar to those of Zagami and Shergotty. We made AR-39-AR-40 analyses of a "plagioclase" (now shock-converted to maskelynite) separate and of a glass hand-picked from a vein connected to shock melt pockets.. Plagioclase was separated using its low magnetic susceptibility and then heavy liquid with density of <2.85 g/cm(exp 3). The AR-39-AR-40 age spectrum of NWA-317 1 plag displays a rise in age over 20-100% of the 39Ar release, from 0.24 Gyr to 0.27 Gy.

  6. APXS ANALYSES OF BOUNCE ROCK: THE FIRST SHERGOTTITE ON MARS

    NASA Technical Reports Server (NTRS)

    Ming, Douglas W.; Zipfel, J.; Anderson, R.; Brueckner, J.; Clark, B. C.; Dreibus, G.; Economou, T.; Gellert, R.; Lugmair, G. W.; Klingelhoefer, G.

    2005-01-01

    During the MER Mission, an isolated rock at Meridiani Planum was analyzed by the Athena instrument suite [1]. Remote sensing instruments noticed its distinct appearance. Two areas on the untreated rock surface and one area that was abraded with the Rock Abrasion Tool were analyzed by Microscopic Imager, Mossbauer Mimos II [2], and Alpha Particle X-ray Spectrometer (APXS). Results of all analyses revealed a close relationship of this rock with known basaltic shergottites.

  7. Sulfur Speciation in the Martian Regolith Component in Shergottite Glasses

    NASA Technical Reports Server (NTRS)

    Rao, M. N.; Nyquist, Laurence E.; Sutton, S.; Huth, J.

    2009-01-01

    We have shown that Gas-Rich Impact-Melt (GRIM) glasses in Shergotty, Zagami, and EET79001 (Lith A and Lith B) contain Martian regolith components that were molten during impact and quenched into glasses in voids of host rock materials based on neutron-capture isotopes, i.e., Sm-150 excesses and Sm-149 deficits in Sm, and Kr-80 excesses produced from Br [1, 2]. These GRIM glasses are rich in S-bearing secondary minerals [3.4]. Evidence for the occurrence of CaSO4 and S-rich aluminosilicates in these glasses is provided by CaO-SO3 and Al2O3-SO3 correlations, which are consistent with the finding of gypsum laths protruding from the molten glass in EET79001 (Lith A) [5]. However, in the case of GRIM glasses from EET79001 (Lith B), Shergotty and Zagami, we find a different set of secondary minerals that show a FeO-SO3 correlation (but no MgOSO3 correlation), instead of CaO-SO3 and Al2O3-SO3 correlations observed in Lith A. These results might indicate different fluidrock interactions near the shergottite source region on Mars. The speciation of sulfur in these salt assemblages was earlier studied by us using XANES techniques [6], where we found that Lith B predominantly contains Fe-sulfide globules (with some sulfate). On the other hand, Lith A showed predominantly Casulfite/ sulfate with some FeS. Furthermore, we found Fe to be present as Fe2+ indicating little oxidation, if any, in these glasses. To examine the sulfide-sulfate association in these glasses, we studied their Fe/Ni ratios with a view to find diagnostic clues for the source fluid. The Fe-sulfide mineral (Fe(0.93)Ni(0.3)S) in EET79001, Lith A is pyrrhotite [7, 8]. It yields an Fe/Ni ratio of 31. In Shergotty, pyrrhotite occurs with a molar ratio of Fe:S of 0.94 and a Ni abundance of 0.12% yielding a Fe/Ni ratio of approx.500 [8]. In this study, we determined a NiO content of approx.0.1% and FeO/NiO ratio of approx.420 in S-rich globules in #507 (EET79001, Lith B) sample using FE-SEM. In the same sample

  8. Enriched Shergottite NWA 5298 As An Evolved Parent Melt: Trace Element Inventory

    NASA Technical Reports Server (NTRS)

    Hui, Hejiu; Peslier, Anne H.; Lapen, Thomas J.; Shafer, John; Brandon, Alan; Irving, Anthony

    2010-01-01

    Martian meteorite Northwest Africa 5298 is a basaltic shergottite that was found near Bir Gandouz (Morocco). Its martian origin was confirmed by oxygen isotopes [1], as well as Mn/Fe ratios in the pyroxenes and K/anorthite ratios in the plagioclases [2]. Here we present a petrographic and geochemical study of NWA 5298. Comparison of mineralogical and geochemical characteristics of this meteorite with other Martian rocks shows that NWA 5298 is not likely paired with any other known shergottites, but it has similarities to another basaltic shergottite Dhofar 378.

  9. Sm-Nd isotopic systematics of lherzolitic shergottite Yamato-793605

    USGS Publications Warehouse

    Misawa, K.; Yamada, K.; Nakamura, N.; Morikawa, N.; Yamashita, K.; Premo, W.R.

    2006-01-01

    We have undertaken Sm-Nd isotopic studies on Yamato-793605 lherzolitic shergottite. The Sm-Nd internal isochron obtained for acid leachates and residues of whole-rock and separated mineral fractions yields an age of 185 ??16 Ma with an initial ??Nd value of +9.7??0.2. The obtained Sm-Nd age is, within analytical errors, identical to the Rb-Sr age of this meteorite as well as to the previous Rb-Sr and Sm-Nd ages of Allan Hills-77005 and Lewis Cliff 88516, although the ??Nd values are not identical to each other. Elemental abundances of lithophile trace elements remain nearly unaffected by aqueous alteration on the Martian surface. The isotopic systems of lherzolitic shergottites, thus, are considered to be indigenous, although disturbances by shock metamorphism are clearly observed. "Young ages of ??? 180 Ma" have been consistently obtained from this and previous Rb-Sr, Sm-Nd and U-Pb isotopic studies and appear to represent crystallization events. ?? 2006 National Institute of Polar Research.

  10. Rare earth patterns in shergottite phosphates and residues

    NASA Technical Reports Server (NTRS)

    Laul, J. C.

    1987-01-01

    Leaching experiments with 1M HCl on ALHA 77005 powder show that rare earth elements (REE) are concentrated in accessory phosphate phases (whitlockite, apatite) that govern the REE patterns of bulk shergottites. The REE patterns of whitlockite are typically light REE-depleted with a negative Eu anomaly and show a hump at the heavy REE side, while the REE pattern of apatite (in Shergotty) is light REE-enriched. Parent magmas are calculated from the modal compositions of residues of ALHA 77005, Shergotty, and EETA 79001. The parent magmas lack a Eu anomaly, indicating that plagioclase was a late-stage crystallizing phase and that it probably crystallized before the phosphates. The parent magmas of ALHA 77005 and Shergotty have similar REE patterns, with a subchondritic Nd/Sm ratio. However, the Sm/Nd isotopoics require a light REE-depleted source for ALHA 77005 (if the crystallization age is less than 600 Myr) and a light REE-enriched source for Shergotty. Distant Nd and Sr isotopic signatures may suggest different source regions for shergottites.

  11. Highly Siderophile Elements in Terrestrial Planets: Evidence From Shergottite Meteorites

    NASA Astrophysics Data System (ADS)

    Brandon, A. D.; Puchtel, I. S.; Walker, R. J.

    2011-12-01

    Mechanisms for the emplacement of highly siderophile elements (HSE) in Earth's mantle have been debated for several decades. The chief conundrum is accounting for the high absolute and chondritic relative abundances of these elements in the terrestrial mantle, despite their strong tendency to partition into metal during core formation. Two end member models are most frequently discussed with respect to this issue. In the first model, abundances of HSE in planetary mantles are controlled by partitioning between segregating metal and silicate at high pressures, where some or all of the HSE may be considerably less siderophile, as may be appropriate for the base of a terrestrial magma ocean. A major weakness of this model is the generally chondritic HSE ratios in the mantle, which would require conditions under which the metal-silicate partitioning of all HSE would converge to approximately the same values. In the second model, termed late accretion, core extraction removes >99% of HSE from the Earth's mantle. The mantle is subsequently reseeded with HSE via continued accretion of 0.5 to 1% by mass of additional material. This model has been questioned because the timing of late accretion is poorly defined, and the mechanisms that can rapidly mix the late accreted materials to homogeneity within the mantle are difficult to envision. To examine this issue, 23 mafic to ultramafic shergottite meteorites from Mars, were measured for 187Re-187Os isotopes and HSE abundances. The objective is to gain insights on the early chemical evolution of the martian mantle to address the issue of HSE controls on the mantles of terrestrial bodies, with Mars serving as an important point of comparison to Earth. The shergottites display calculated initial 187Os/188Os ratios that correlate with the initial 143Nd/144Nd. Shergottites from mantle sources with long-term melt-depleted characteristics (initial ɛ143Nd of +36 to +40) have chondritic initial γ187Os ranging from -0.5 to +2

  12. Lead Isotope Compositions of Acid Residues from Olivine-Phyric Shergottite Tissint: Implications for Heterogeneous Shergottite Source Reservoirs

    NASA Technical Reports Server (NTRS)

    Moriwaki, R.; Usui, T.; Yokoyama, T.; Simon, J. I.; Jones, J. H.

    2015-01-01

    Geochemical studies of shergottites suggest that their parental magmas reflect mixtures between at least two distinct geochemical source reservoirs, producing correlations between radiogenic isotope compositions and trace element abundances. These correlations have been interpreted as indicating the presence of a reduced, incompatible element- depleted reservoir and an oxidized, incompatible- element-enriched reservoir. The former is clearly a depleted mantle source, but there is ongoing debate regarding the origin of the enriched reservoir. Two contrasting models have been proposed regarding the location and mixing process of the two geochemical source reservoirs: (1) assimilation of oxidized crust by mantle derived, reduced magmas, or (2) mixing of two distinct mantle reservoirs during melting. The former requires the ancient Martian crust to be the enriched source (crustal assimilation), whereas the latter requires isolation of a long-lived enriched mantle domain that probably originated from residual melts formed during solidification of a magma ocean (heterogeneous mantle model). This study conducts Pb isotope and trace element concentration analyses of sequential acid-leaching fractions (leachates and the final residues) from the geochemically depleted olivine-phyric shergottite Tissint. The results suggest that the Tissint magma is not isotopically uniform and sampled at least two geochemical source reservoirs, implying that either crustal assimilation or magma mixing would have played a role in the Tissint petrogenesis.

  13. Jarosite in the Shergottite Que 94201

    NASA Technical Reports Server (NTRS)

    Ross, D. K.; Ito, M.; Rao, M. N.; Hervig, R.; Williams, L. B.; Nyquist, Laurence E.; Peslier, A.

    2010-01-01

    Veins of the hydroxylated, potassium ferric sulfate mineral jarosite - KFe3(SO4)2(OH)6 - have been identified in the martian meteorite Queen Alexandra Range (QUE) 94201. Iron potassium sulfate had been reported in QUE 94201 by Wentworth and Gooding. Jarosite has been reported in other Martian meteorites - Roberts Massif (RBT) 04262, Miller Range (MIL) 03346, and Yamato 000593 - and it has been identified on the Martian surface by Moessbauer spectroscopy. Given the presence of jarosite on Mars, and the burgeoning interest in water-rock interactions on Mars, the question arises whether jarosite in Martian meteorites is formed by aqueous alteration on Mars, or in Antarctica. Hydrogen isotopes are potentially sensitive indicators of the site of formation or last equilibration of hydrous alteration minerals, because of the large difference between D/H ratio of the Martian atmosphere (and also presumably the cryosphere) and terrestrial hydrogen. The Martian atmospheric delta D(sub SMOW) ratio is approximately +4200%o, igneous minerals with substantial hydrogen (phosphates) have high D, +2000%o to +4700%o versus terrestrial waters with approximately 480%o to +130%o. The crystal chemistry and structure of jarosite are reviewed in Papi ke et al. Here we report hydrogen isotopes measured in jarosite in QUE 94201 by ion microprobe, and also report on the major element composition of jarosite measured by electron microprobe.

  14. Cathodoluminescence Characterization of Maskelynite and Alkali Feldspar in Shergottite (Dhofar 019)

    SciTech Connect

    Kayama, M.; Nakazato, T.; Nishido, H.; Ninagawa, K.; Gucsik, A.

    2009-08-17

    Dhofar 019 is classified as an olivine-bearing basaltic shergottite and consists of subhedral grains of pyroxene, olivine, feldspar mostly converted to maskelynite and minor alkali feldspar. The CL spectrum of its maskelynite exhibits an emission band at around 380 nm. Similar UV-blue emission has been observed in the plagioclase experimentally shocked at 30 and 40 GPa, but not in terrestrial plagioclase. This UV-blue emission is a notable characteristic of maskelynite. CL spectrum of alkali feldspar in Dhofar 019 has an emission bands at around 420 nm with no red emission. Terrestrial alkali feldspar actually consists of blue and red emission at 420 and 710 nm assigned to Al-O{sup -}-Al and Fe{sup 3+} centers, respectively. Maskelynite shows weak and broad Raman spectral peaks at around 500 and 580 cm{sup -1}. The Raman spectrum of alkali feldspar has a weak peak at 520 cm{sup -1}, whereas terrestrial counterpart shows the emission bands at 280, 400, 470, 520 and 1120 cm{sup -1}. Shock pressure on this meteorite transformed plagioclase and alkali feldspar into maskelynite and almost glass phase, respectively. It eliminates their luminescence centers, responsible for disappearance of yellow and/or red emission in CL of maskelynite and alkali feldspar. The absence of the red emission band in alkali feldspar can also be due to the lack of Fe{sup 3+} in the feldspar as it was reported for some lunar feldspars.

  15. Martian Pyroxenes in the Shergottite Meteorites; Zagami, SAU005, DAG476 and EETA79001

    NASA Astrophysics Data System (ADS)

    Stephen, N.; Benedix, G. K.; Bland, P.; Hamilton, V. E.

    2010-12-01

    The geology and surface mineralogy of Mars is characterised using remote sensing techniques such as thermal emission spectroscopy (TES) from instruments on a number of spacecraft currently orbiting Mars or gathered from roving missions on the Martian surface. However, the study of Martian meteorites is also important in efforts to further understand the geological history of Mars or to interpret mission data as they are believed to be the only available samples that give us direct clues as to Martian igneous processes [1]. We have recently demonstrated that the spectra of Martian-specific minerals can be determined using micro-spectroscopy [2] and that these spectra can be reliably obtained from thin sections of Martian meteorites [3]. Accurate modal mineralogy of these meteorites is also important [4]. In this study we are using a variety of techniques to build upon previous studies of these particular samples in order to fully characterise the nature of the 2 common pyroxenes found in Martian Shergottites; pigeonite and augite [5], [6]. Previous studies have shown that the Shergottite meteorites are dominated by pyroxene (pigeonite and augite in varying quantities) [4], [5], commonly but not always olivine, plagioclase or maskelynite/glass and also hydrous minerals, which separate the Martian meteorites from other achondrites [7]. Our microprobe study of meteorites Zagami, EETA79001, SAU005 and DAG476 in thin-section at the Natural History Museum, London shows a chemical variability within both the pigeonite and augite composition across individual grains in all thin sections; variation within either Mg or Ca concentration varies from core to rim within the grains. This variation can also be seen in modal mineralogy maps using SEM-derived element maps and the Photoshop® technique previously described [4], and in new micro-spectroscopy data, particularly within the Zagami meteorite. New mineral spectra have been gathered from the Shergottite thin-sections by

  16. Constraints on the Parental Melts of Enriched Shergottites from Image Analysis and High Pressure Experiments

    NASA Technical Reports Server (NTRS)

    Collinet, M.; Medard, E.; Devouard, B.; Peslier, A.

    2012-01-01

    Martian basalts can be classified in at least two geochemically different families: enriched and depleted shergottites. Enriched shergottites are characterized by higher incompatible element concentrations and initial Sr-87/Sr-86 and lower initial Nd-143/Nd-144 and Hf-176/Hf-177 than depleted shergottites [e.g. 1, 2]. It is now generally admitted that shergottites result from the melting of at least two distinct mantle reservoirs [e.g. 2, 3]. Some of the olivine-phyric shergottites (either depleted or enriched), the most magnesian Martian basalts, could represent primitive melts, which are of considerable interest to constrain mantle sources. Two depleted olivine-phyric shergottites, Yamato (Y) 980459 and Northwest Africa (NWA) 5789, are in equilibrium with their most magnesian olivine (Fig. 1) and their bulk rock compositions are inferred to represent primitive melts [4, 5]. Larkman Nunatak (LAR) 06319 [3, 6, 7] and NWA 1068 [8], the most magnesian enriched basalts, have bulk Mg# that are too high to be in equilibrium with their olivine megacryst cores. Parental melt compositions have been estimated by subtracting the most magnesian olivine from the bulk rock composition, assuming that olivine megacrysts have partially accumulated [3, 9]. However, because this technique does not account for the actual petrography of these meteorites, we used image analysis to study these rocks history, reconstruct their parent magma and understand the nature of olivine megacrysts.

  17. Fe3+ partitioning during basalt differentiation on Mars: insights into the oxygen fugacity of the shergottite mantle source(s).

    NASA Astrophysics Data System (ADS)

    Medard, E.; Martin, A. M.; Collinet, M.; Righter, K.; Grove, T. L.; Newville, M.; Lanzirotti, A.

    2014-12-01

    primitive shergottites record a mantle fO2 around FMQ-2.5, consistent with the lowest fO2estimated for surface basalts [5]. [1] McCanta et al. (2004) Am Min 89:1685-1693; [2] Mallmann and O'Neill (2009) J Petrol 50:1765-1794; [3] Righter et al. (2013) Am Min 98:616-628; [4] Kress and Carmichael (1991) CMP 108:82-92; [5] Schmidt ME et al. (2014) EPSL 384:198-208.

  18. An "Andesitic" Component in Shergottites with Restored LREE Abundances?

    NASA Technical Reports Server (NTRS)

    Nyquist, L. E.; Shih, C.-Y.; Wiesmann, H.; Barrat, J. A.

    2002-01-01

    The shergottite Martian meteorites present a variety of oft-confusing petrologic features. In particular, represented among this subgroup are basalts with very depleted LREE abundances, as well as those with nearly chondritic overall REE abundances. The LREE-depleted basalts appear to more closely record the REE and isotopic features of their mantle source legions. Those basalts with more nearly chondritic REE abundances appear to contain an extra component often referred to as a "crustal" component. The addition of the crustal component tends to restore the overall REE abundance pattern towards chondritic relative abundances. Here we suggest that the crustal component could derive from andesitic rocks observed remotely to occur on the Martian surface, and which were analysed at the Pathfinder site.

  19. An "Andestic" Component in Shergottites with Restored LREE Abundances?

    NASA Technical Reports Server (NTRS)

    Nyquist, L. E.; Shih, C.-Y.; Wiesmann, H.; Barrat, J. A.

    2002-01-01

    The shergottite Martian meteorites present a variety of oft-confusing petrologic features. In particular, represented among this subgroup are basalts with very depleted LREE abundances, as well as those with nearly chondritic overall REE abundances. The LREE-depleted basalts appear to more closely record the REE and isotopic features of their mantle source regions. Those basalts with more nearly chondritic REE abundances appear to contain an extra component often referred to as a "crustal" component. The addition of the crustal component tends to restore the overall REE abundance pattern towards chondritic relative abundances. Here we suggest that the crustal component could derive from "andesitic" rocks observed remotely to occur on the Martian surface, and which were analysed at the Pathfinder site.

  20. Petrology and trace element geochemistry of Tissint, the newest shergottite fall

    NASA Astrophysics Data System (ADS)

    Balta, J. Brian; Sanborn, Matthew E.; Udry, Arya; Wadhwa, Meenakshi; McSween, Harry Y.

    2015-01-01

    AbstractThe fall and recovery of the Tissint meteorite in 2011 created a rare opportunity to examine a Martian sample with a known, short residence time on Earth. Tissint is an olivine-phyric <span class="hlt">shergottite</span> that accumulated olivine antecrysts within a single magmatic system. Coarse olivine grains with nearly homogeneous cores of Mg# >80 suggest slow re-equilibration. Many macroscopic features of this sample resemble those of LAR 06319, including the olivine crystal size distribution and the presence of evolved oxide and olivine compositions. Unlike LAR 06319, however, no magmatic hydrous phases were found in the analyzed samples of Tissint. Minor and trace element compositions indicate that the meteorite is the product of closed-system crystallization from a parent melt derived from a depleted source, with no obvious addition of a LREE-rich (crustal?) component prior to or during crystallization. The whole-rock REE pattern is similar to that of intermediate olivine-phyric <span class="hlt">shergottite</span> EETA 79001 lithology A, and could also be approximated by a more olivine-rich version of depleted basaltic <span class="hlt">shergottite</span> QUE 94201. Magmatic oxygen fugacities are at the low end of the <span class="hlt">shergottite</span> range, with log fO2 of QFM-3.5 to -4.0 estimated based on early-crystallized minerals and QFM-2.4 estimated based on the Eu in pyroxene oxybarometer. These values are similarly comparable to other depleted <span class="hlt">shergottites</span>, including SaU 005 and QUE 94201. Tissint occupies a previously unsampled niche in <span class="hlt">shergottite</span> chemistry: containing olivines with Mg# >80, resembling the enriched olivine-phyric <span class="hlt">shergottite</span> LAR 06319 in its crystallization path, and comparable to intermediate olivine-phyric <span class="hlt">shergottite</span> EETA 79001A, depleted olivine-phyric <span class="hlt">shergottite</span> DaG 476, and depleted basaltic <span class="hlt">shergottite</span> QUE 94201 in its trace element abundances and oxygen fugacity. The apparent absence of evidence for terrestrial alteration in Tissint</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_1");'>1</a></li> <li><a href="#" onclick='return showDiv("page_2");'>2</a></li> <li class="active"><span>3</span></li> <li><a href="#" onclick='return showDiv("page_4");'>4</a></li> <li><a href="#" onclick='return showDiv("page_5");'>5</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_3 --> <div id="page_4" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_2");'>2</a></li> <li><a href="#" onclick='return showDiv("page_3");'>3</a></li> <li class="active"><span>4</span></li> <li><a href="#" onclick='return showDiv("page_5");'>5</a></li> <li><a href="#" onclick='return showDiv("page_6");'>6</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="61"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20080026134','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20080026134"><span id="translatedtitle">Concordant Rb-Sr and Sm-Nd Ages for NWA 1460: A 340 Ma Old Basaltic <span class="hlt">Shergottite</span> Related to Lherzolitic <span class="hlt">Shergottites</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Nyquist, L. E.; Shih, C-Y; Reese, Y. D.; Irving, A. J.</p> <p>2006-01-01</p> <p>Preliminary Rb-Sr and Sm-Nd ages reported by [1] for the NWA 1460 basaltic <span class="hlt">shergottite</span> are refined to 336+/-14 Ma and 345+/-21 Ma, respectively. These concordant ages are interpreted as dating a lava flow on the Martian surface. The initial Sr and Nd isotopic compositions of NWA 1460 suggest it is an earlier melting product of a Martian mantle source region similar to those of the lherzolitic <span class="hlt">shergottites</span> and basaltic <span class="hlt">shergottite</span> EETA79001, lithology B. We also examine the suggestion that generally "young" ages for other Martian meteorites should be reinterpreted in light of Pb-207/Pb-206 - Pb-204/Pb-206 isotopic systematics [2]. Published U-Pb isotopic data for nakhlites are consistent with ages of approx.1.36 Ga. The UPb isotopic systematics of some Martian <span class="hlt">shergottites</span> and lherzolites that have been suggested to be approx.4 Ga old [2] are complex. We nevertheless suggest the data are consistent with crystallization ages of approx.173 Ma when variations in the composition of in situ initial Pb as well as extraneous Pb components are considered.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=1983LPSC...14..229S&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=1983LPSC...14..229S&link_type=ABSTRACT"><span id="translatedtitle">Mineral chemistry of the <span class="hlt">shergottites</span>, nakhlites, Chassigny, Brachina, pallasites and urelites</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Smith, J. V.; Steele, I. M.; Leitch, C. A.</p> <p>1983-11-01</p> <p>The mineral chemistry is compared for selected achondrites. Olivine in the ALHA 77005 and EETA 79001 <span class="hlt">shergottites</span>, olivine-rich Chassigny and Brachina, and the nakhlites, contains Ni indicative of oxidizing conditions, whereas pallasitic and ureilitic olivines contain much lower Ni due to reducing conditions. The Brachina olivine and pyroxene have distinctively higher Fe/Mn than the <span class="hlt">shergottites</span> and Chassigny, further indicating that Brachina is unique. The Chassigny and 77005 olivines contain lower Cr2O3 (0.03 wt. pct) than the Brachina and 79001 olivines. Values of Fe/Mn for cumulus augites in nakhlites are higher than for the <span class="hlt">shergottites</span>, whereas those for ferropigeonites are not. The 77005 <span class="hlt">shergottite</span> contains troilite FeS in contrast to 79001, Shergotty, Zagami, and Chassigny, which contain pyrrhotite. Further analyses are needed, but the present survey indicates that at least Brachina is not chemically cogenetic with the other 'oxidized achondrites', and that the Fe/Mn ratio of the cumulus augites in nakhlites is a problem for the assignment of the nakhlites, <span class="hlt">shergottites</span>, and Chassigny to a single genetic group.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20090022361','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20090022361"><span id="translatedtitle">Rb-Sr Isotopic Studies Of Antarctic Lherzolitic <span class="hlt">Shergottite</span> Yamato 984028</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Shih, C.-Y.; Nyquist, L. E.; Reese, Y.; Misawa, K.</p> <p>2009-01-01</p> <p>Yamato 984028 is a Martian meteorite found in the Yamato Mountains of Antarctica. It is classified as a lherzolitic <span class="hlt">shergottite</span> and petrographically resembles several other lherzolitic <span class="hlt">shergottites</span>, i.e. ALHA 77005, LEW 88516, Y-793605 and Y-000027/47/97 [e.g. 2-5]. These meteorites have similarly young crystallization ages (152-185 Ma) as enriched basaltic <span class="hlt">shergottites</span> (157-203 Ma), but have very different ejection ages (approximately 4 Ma vs. approximately 2.5 Ma), thus they came from different martian target crater areas. Lherzolitic <span class="hlt">shergottites</span> have mg-values approximately 0.70 and represent the most mafic olivine-pyroxene cumulates. Their parental magmas were melts derived probably from the primitive Martian mantle. Here we present Rb-Sr isotopic data for Y-984028 and compare these data with those obtained from other lherzolitic and olivine-phyric basaltic <span class="hlt">shergottites</span> to better understand the isotopic characteristics of their primitive mantle source regions. Corresponding Sm-Nd analyses for Y-984028 are in progress.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20150001623','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20150001623"><span id="translatedtitle">Melt Inclusion Analysis of RBT 04262 with Relationship to <span class="hlt">Shergottites</span> and Mars Surface Compositions</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Potter, S. A.; Brandon, A. D.; Peslier, A. H.</p> <p>2015-01-01</p> <p>Martian meteorite RBT 04262 is in the <span class="hlt">shergottite</span> class. It displays the two lithologies typically found in "lherzolitic <span class="hlt">shergottites</span>": one with a poikilitic texture of large pyroxene enclosing olivine and another with non-poikilitic texture. In the case of RBT 04262, the latter strongly ressembles an olivine- phyric <span class="hlt">shergottite</span> which led the initial classification of this meteorite in that class. RBT 04262 has been studied with regards to its petrology, geochemistry and cosmic ray exposure and belongs to the enriched oxidized end-member of the <span class="hlt">shergottites</span>. Studies on RBT 04262 have primarily focused on the bulk rock composition or each of the lithologies independently. To further elucidate RBT 04262's petrology and use it to better understand Martian geologic history, an in-depth study of its melt inclusions (MI) is being conducted. The MI chosen for this study are found within olivine grains. MI are thought to be trapped melts of the crystallizing magma preserved by the encapsulating olivine and offer snapshots of the composition of the magma as it evolves. Some MI, in the most Mg-rich part of the olivine of olivine-pyric <span class="hlt">shergottites</span>, may even be representative of the meteorite parent melt.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19840035683&hterms=PYRRHOTITE&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3DPYRRHOTITE','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19840035683&hterms=PYRRHOTITE&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3DPYRRHOTITE"><span id="translatedtitle">Mineral chemistry of the <span class="hlt">shergottites</span>, nakhlites, Chassigny, Brachina, pallasites and urelites</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Smith, J. V.; Steele, I. M.; Leitch, C. A.</p> <p>1983-01-01</p> <p>The mineral chemistry is compared for selected achondrites. Olivine in the ALHA 77005 and EETA 79001 <span class="hlt">shergottites</span>, olivine-rich Chassigny and Brachina, and the nakhlites, contains Ni indicative of oxidizing conditions, whereas pallasitic and ureilitic olivines contain much lower Ni due to reducing conditions. The Brachina olivine and pyroxene have distinctively higher Fe/Mn than the <span class="hlt">shergottites</span> and Chassigny, further indicating that Brachina is unique. The Chassigny and 77005 olivines contain lower Cr2O3 (0.03 wt. pct) than the Brachina and 79001 olivines. Values of Fe/Mn for cumulus augites in nakhlites are higher than for the <span class="hlt">shergottites</span>, whereas those for ferropigeonites are not. The 77005 <span class="hlt">shergottite</span> contains troilite FeS in contrast to 79001, Shergotty, Zagami, and Chassigny, which contain pyrrhotite. Further analyses are needed, but the present survey indicates that at least Brachina is not chemically cogenetic with the other 'oxidized achondrites', and that the Fe/Mn ratio of the cumulus augites in nakhlites is a problem for the assignment of the nakhlites, <span class="hlt">shergottites</span>, and Chassigny to a single genetic group.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19870038806&hterms=Beryllium&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3DBeryllium','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19870038806&hterms=Beryllium&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3DBeryllium"><span id="translatedtitle">Beryllium-10 contents of <span class="hlt">shergottites</span>, nakhlites, and Chassigny</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Pal, D. K.; Tuniz, C.; Moniot, R. K.; Savin, W.; Kruse, T.</p> <p>1986-01-01</p> <p>Accelerator mass spectrometry gives the following Be-10 contents (dpm/kg) for the SNC meteorites: Shergotty, 13.0 + or - 1.5 and 17.3 + or - 2.7; Zagami, 18.6 + or - 2.5 and 20.0 + or - 3.2; ALHA 77005, 15 + or - 3; EETA 79001A, 7.8 + or - 1.1 and 6.3 + or - 0.5; EETA 79001B, 8.5 + or - 1.1; Nakhla, 19.7 + or - 3.3; Lafayette, 18.1 + or - 2.5; Governador Valadares, 25.6 + or - 3.6; Chassigny, 20.5 + or - 3.1. The Be-10 contents of the NC meteorites indicate that significant accumulation of cosmogenic nuclides occurred in decimeter rather than planetary-size bodies. The agreement of the He-3, Ne-21, and Be-10 exposure ages of the <span class="hlt">shergottites</span> also supports small-body irradiation. A long terrestrial age for EETA 79001 appears unlikely.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19980018466','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19980018466"><span id="translatedtitle">The <span class="hlt">Shergottite</span> Age Paradox and the Relative Probabilities of Ejecting Martian Meteorites of Differing Ages</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Borg, L. E.; Shih, C.-Y.; Nyquist, L. E.</p> <p>1998-01-01</p> <p>The apparent paradox that the majority of impacts yielding Martian meteorites appear to have taken place on only a few percent of the Martian surface can be resolved if all the <span class="hlt">shergottites</span> were ejected in a single event rather than in multiple events as expected from variations in their cosmic ray exposure and crystallization ages. If the <span class="hlt">shergottite</span>-ejection event is assigned to one of three craters in the vicinity of Olympus Mons that were previously identified as candidate source craters for the SNC (<span class="hlt">Shergottites</span>, Nakhlites, Chassigny) meteorites, and the nakhlite event to another candidate crater in the vicinity of Ceraunius Tholus, the implied ages of the surrounding terranes agree well with crater density ages. EN,en for high cratering rates (minimum ages), the likely origin of the <span class="hlt">shergottites</span> is in the Tharsis region, and the paradox of too many meteorites from too little terrane remains for multiple <span class="hlt">shergottite</span>-ejection events. However, for high cratering rates it is possible to consider sources for the nakhlltes which are away from the Tharsis region. The meteorite-yielding impacts may have been widely dispersed with sources of the young SNC meteorites in the northern plains, and the source of the ancient orthopyroxenite, ALH84001, in the ancient southern uplands. Oblique-impact craters can be identified with the sources of the nakhlites and the orthopyroxenite,, respectively, in the nominal cratering rate model, and with the <span class="hlt">shergottites</span> and orthopyroxenite, respectively, in the high cratering rate model. Thus, oblique impacts deserve renewed attention as an ejection mechanism for Martian meteorites.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20130003564','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20130003564"><span id="translatedtitle">Water in Nominally Anhydrous Minerals from Nakhlites and <span class="hlt">Shergottites</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Peslier, Anne H.</p> <p>2013-01-01</p> <p>Estimating the amount of water in the interior of terrestrial planets has tremendous implications on our understanding of solar nebula evolution, planet formation and geological history, and extraterrestrial volcanism. Mars has been a recent focus of such enquiry with complementary datasets from spacecrafts, rovers and martian meteorite studies. In planetary interiors, water can be dissolved in fluids or melts and hydrous phases, but can also be locked as protons attached to structural oxygen in lattice defects in nominally anhydrous minerals (NAM) such as olivine, pyroxene, or feldspar [1-3]. Measuring water in Martian meteorite NAM is challenging because the minerals are fragile and riddled with fractures from impact processes that makes them break apart during sample processing. Moreover, curing the sample in epoxy causes problems for the two main water analysis techniques, Fourier transform infrared spectrometry (FTIR) and secondary ionization mass spectrometry (SIMS). Measurements to date have resulted in a heated debate on how much water the mantle of Mars contains. SIMS studies of NAM [4], amphiboles [5], and apatites [6-8] from Martian meteorites report finding enough water in these phases to infer that the martian mantle is as hydrous as that of the Earth. On the other hand, a SIMS study of glass in olivine melt inclusions from <span class="hlt">shergottites</span> concludes that the Martian mantle is much drier [9]. The latter interpretation is also supported by the fact that most martian hydrous minerals generally have the relevant sites filled with Cl and F instead of H [10,11]. As for experimental results, martian basalt compositions can be reproduced using water as well as Cl in the parent melts [12,13]. Here FTIR is used to measure water in martian meteorite minerals in order to constrain the origin of the distribution of water in martian meteorite phases.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20110007848','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20110007848"><span id="translatedtitle">Rb-Sr And Sm-Nd Ages, and Petrogenesis of Depleted <span class="hlt">Shergottite</span> Northwest Africa 5990</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Shih, C. Y.; Nyquist, L. E.; Reese, Y.; Irving, A. J.</p> <p>2011-01-01</p> <p>Northwest Africa (NWA) 5990 is a very fresh Martian meteorite recently found on Hamada du Draa, Morocco and was classified as an olivine-bearing diabasic igneous rock related to depleted <span class="hlt">shergottites</span> [1]. The study of [1] also showed that NWA 5990 resembles QUE 94201 in chemical, textural and isotopic aspects, except QUE 94201 contains no olivine. The depleted <span class="hlt">shergottites</span> are characterized by REE patterns that are highly depleted in LREE, older Sm-Nd ages of 327-575 Ma and highly LREE-depleted sources with Nd= +35+48 [2-7]. Age-dating these samples by Sm-Nd and Rb-Sr methods is very challenging because they have been strongly shocked and contain very low abundances of light rare earth elements (Sm and Nd), Rb and Sr. In addition, terrestrial contaminants which are commonly present in desert meteorites will compromise the equilibrium of isotopic systems. Since NWA 5990 is a very fresh meteorite, it probably has not been subject to significant desert weathering and thus is a good sample for isotopic studies. In this report, we present Rb-Sr and Sm-Nd isotopic results for NWA 5990, discuss the correlation of the determined ages with those of other depleted <span class="hlt">shergottites</span>, especially QUE 94201, and discuss the petrogenesis of depleted <span class="hlt">shergottites</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20070000533','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20070000533"><span id="translatedtitle">Ar-Ar Age of NWA-1460 and Evidence For Young Formation Ages of the <span class="hlt">Shergottites</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Bogard, Donald D.; Park, Jisun</p> <p>2006-01-01</p> <p>Agreement of Ar-Ar, Sm-Nd, and Rb-Sr ages for NWA1460, and the inconsistency between a low shock-heating temperature for Zagami and the proposition that a 4.0 Gyr-old Zagami lost most of its Ar-40 are inconsistent with ancient formation ages for these <span class="hlt">shergottites</span>, but are consistent with relatively young igneous formation ages.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015M%26PS..tmp..249H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015M%26PS..tmp..249H"><span id="translatedtitle">Petrography and geochemistry of the enriched basaltic <span class="hlt">shergottite</span> Northwest Africa 2975</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>He, Qi; Xiao, Long; Balta, J. Brian; Baziotis, Ioannis P.; Hsu, Weibiao; Guan, Yunbin</p> <p>2015-11-01</p> <p>We present a study of the petrology and geochemistry of basaltic <span class="hlt">shergottite</span> Northwest Africa 2975 (NWA 2975). NWA 2975 is a medium-grained basalt with subophitic to granular texture. Electron microprobe (EMP) analyses show two distinct pyroxene compositional trends and patchy compositional zoning patterns distinct from those observed in other meteorites such as Shergotty or QUE 94201. As no bulk sample was available to us for whole rock measurements, we characterized the fusion crust and its variability by secondary ion mass spectrometer (SIMS) measurements and laser ablation inductively coupled plasma spectroscopy (LA-ICP-MS) analyses as a best-available proxy for the bulk rock composition. The fusion crust major element composition is comparable to the bulk composition of other enriched basaltic <span class="hlt">shergottites</span>, placing NWA 2975 within that sample group. The CI-normalized REE (rare earth element) patterns are flat and also parallel to those of other enriched basaltic <span class="hlt">shergottites</span>. Merrillite is the major REE carrier and has a flat REE pattern with slight depletion of Eu, parallel to REE patterns of merrillites from other basaltic <span class="hlt">shergottites</span>. The oxidation state of NWA 2975 calculated from Fe-Ti oxide pairs is NNO-1.86, close to the QFM buffer. NWA 2975 represents a sample from the oxidized and enriched <span class="hlt">shergottite</span> group, and our measurements and constraints on its origin are consistent with the hypothesis of two distinct Martian mantle reservoirs: a reduced, LREE-depleted reservoir and an oxidized, LREE-enriched reservoir. Stishovite, possibly seifertite, and dense SiO2 glass were also identified in the meteorite, allowing us to infer that NWA 2975 experienced a realistic shock pressure of ~30 GPa.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014AGUFM.P43D4010B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014AGUFM.P43D4010B"><span id="translatedtitle">Comparing MSL ChemCam Analyses to <span class="hlt">Shergottite</span> and Terrestrial Rock Types</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Bridges, J.; Edwards, P.; Dyar, M. D.; Fisk, M. R.; Schwenzer, S. P.; Forni, O.; Wiens, R. C.</p> <p>2014-12-01</p> <p>The ChemCam instrument on Mars Science Laboratory determines the elemental composition of target areas at ≤6m range, and has acquired over 145000 spectra. Here we use the individual shots and averaged targets with the PLS1 dataset on both outcrops and float rocks. Various localities were sampled, including Rocknest, Sheepbed, Shaler, Cooperstown, Darwin and Kimberley. Rocknest and Sheepbed shots have quite homogeneous, basaltic compositions with Gini factors of 0.66 and 0.67 respectively (a Gini factor of 0 indicates a completely homogeneous dataset). Shaler is similarly homogeneous with a Gini factor 0.62 but is more felsic in composition. Darwin and Kimberley both follow a basaltic mixing trend between pyroxene and alkali feldspars. They have a heterogeneous spread with factors of 0.77 and 0.74. Kimberley and Darwin are the most alkaline outcrops, and then Shaler, finally Sheepbed and Rocknest are the least alkaline. The Na2O and K2O contents are controlled by variable abundances of alkaline feldspars. Many float rocks were also analysed. They include samples with mm-sized, visible feldspar grains, which are probable phenocrysts and cumulate grains. These rocks likely come from different sources as their compositions are quite heterogeneous e.g. the Gini factor for the whole set of feldspar-rich float rocks is 0.76 (using an average composition for each target). We compare these compositions with data from the MER APXS, and from this we can see that the float rocks sampled by MSL are closer to the alkaline feldspar end of the basaltic mixing trend than the more FeO+MgO-rich MER basalts (e.g. Rieder et <span class="hlt">al</span>. 2004 10.1126/science.1104358) The basaltic <span class="hlt">shergottite</span> meteorites also have higher FeO+MgO contents and lower <span class="hlt">Al</span>2O3 than the MSL rocks. When compared on <span class="hlt">Al</span>2O3-(FeOMgO)-(Na2OK2O)-CaO and other plots, the float rocks have compositions similar to a spread between terrestrial diorite and gabbro, though some have high Na2O+K2O contents.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20150002838','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20150002838"><span id="translatedtitle">Gusev-Meridiani-Type Soil Component Dissolved in Some Shock Glasses in <span class="hlt">Shergottites</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Ross, D. K.; Rao, M. N.; Nyquist, L. E.; Shi, C. Y.; Sutton, S.; Harrison, D. H.</p> <p>2015-01-01</p> <p>Modal analysis, based on APXS, MiniTES and Mossbauer results obtained at Gusev and Meridiani sites on Mars, indicates that Martian soils consist predominantly of igneous minerals such as olivine, pyroxene and feldspar (approximately70 - 80%), with the balance consisting of alteration minerals such as sulfates, silica and chlorides]. These studies also showed that soil alteration did not occur in-situ and igneous and alteration components are derived from different sources. Below, we analyse the chemical abundance data obtained from shock glasses in <span class="hlt">shergottites</span> using mass balance mixing models. In these models, the two main end members used are (a) host rock chemical composition and (b) the GM soils average composition as the second component. Here, we consider the S-bearing phases as indicators of added alteration phases in the shock glasses and GM soils. Although the S-bearing phase in shock glasses occurs as micron sized sulfide blebs, we showed in earlier abstracts that sulfur was originally present as sulfate in impact glass-precursor materials and was subsequently reduced to sulfide during shock melting. This conclusion is based on results obtained from S-K XANES studies, Fe/S atomic ratios in sulfide blebs and 34S/32S isotopic measurements in these sulfide blebs. Additionally, sulfur in several EET79001 Lith. A glasses is found to correlate positively with <span class="hlt">Al</span>2O3 and CaO (and negatively with FeO and MgO), suggesting the presence of <span class="hlt">Al</span>- and Ca- sul-fate-bearing phases. The distribution of the 87Sr/86Sr iso-topic ratios determined in Lith. A glasses (,27 &,188 and,54) indicate that Martian soil gypsum and host rock material were mixed with each other in the glass precursors. In some vugs in Lith A glass,27 detected gypsum laths. Furthermore, the Martian regolith-de-rived component (where sulfur typically occurs as sul-fate) is identified in these glasses by determining neutron produced isotopic excesses/deficits in 80Kr and 149Sm isotopes. Moreover, the</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19860063607&hterms=earth+formation&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D70%26Ntt%3Dearth%2Bformation','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19860063607&hterms=earth+formation&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D70%26Ntt%3Dearth%2Bformation"><span id="translatedtitle">Core formation in the earth and <span class="hlt">shergottite</span> parent body (SPB) - Chemical evidence from basalts</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Treiman, A. H.; Drake, M. J.; Janssens, M.-J.; Wolf, R.; Ebihara, M.</p> <p>1986-01-01</p> <p>Abundances of siderophile and chalcophile elements in the <span class="hlt">shergottite</span> parental body (SPB) have been compared with those of the earth. To this end, new INAA and RNAA analyses of non-Antarctic meteorites have been performed, and the composition of the <span class="hlt">shergottite</span> SPB mantle has been inferred from the compositions of the SNC meteorites. The composition of the earth's mantle has been inferred from the compositions of terrestrial basalt. Finally, the effects of volatile depletion, core formation, and mineral/melt fractionation on the abundances of siderophile and chalcophile elements in the SPB and the earth have been taken into consideration. Compared to the earth, the SPB mantle is richer in moderately siderophile elements and more depleted with respect to chalcophile elements. The observed relative abundances of siderophile and chalcophile elements in the SPB and the earth mantles indicate that the SPB underwent accretion and/or differentiation processes which differ from those in the earth.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19940016396&hterms=elephant&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D90%26Ntt%3Delephant','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19940016396&hterms=elephant&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D90%26Ntt%3Delephant"><span id="translatedtitle">Weathering features and secondary minerals in Antarctic <span class="hlt">Shergottites</span> ALHA77005 and LEW88516</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Wentworth, Susan J.; Gooding, James L.</p> <p>1993-01-01</p> <p>Previous work has shown that all three sub-groups of the <span class="hlt">shergottite</span>, nakhlite, and chassignite (SNC) clan of meteorites contain aqueous precipitates of probable pre-terrestrial origin. In the context of secondary minerals, the most thoroughly studied <span class="hlt">shergottite</span> has been Elephant Moraine, Antarctica A79001 (EETA79001). The recognition of LEW88516 as the latest SNC specimen, and its close similarity with ALHA77005, invite a comparative study of the latter two meteorites, and with EETA79001, from the perspective of aqueous alteration. The fusion crusts of the two meteorites are quite similar except that ALHA77005 is more vesicular (possibly indicating a higher indigenous volatile content). Secondary aluminosilicates (and salts on LEW88516) of definite Antarctic origin partially fill vesicles and fractures on both fusion crusts. Interior samples of the two meteorites are grossly similar in that traces of secondary minerals are present in both.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20150002847','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20150002847"><span id="translatedtitle">Correlations Between Surficial Sulfur and a REE Crustal Assimilation Signature in Martian <span class="hlt">Shergottites</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Jones, J. H.; Franz, H. B.</p> <p>2015-01-01</p> <p>Compared to terrestrial basalts, the Martian <span class="hlt">shergottite</span> meteorites have an extraordinary range of Sr and Nd isotopic signatures. In addition, the S isotopic compositions of many <span class="hlt">shergottites</span> show evidence of interaction with the Martian surface/ atmosphere through mass-independent isotopic fractionations (MIF, positive, non-zero delta(exp 33)S) that must have originated in the Martian atmosphere, yet ultimately were incorporated into igneous sulfides (AVS - acid-volatile sulfur). These positive delta(exp 33)S signatures are thought to be governed by solar UV photochemical processes. And to the extent that S is bound to Mars and not lost to space from the upper atmosphere, a positive delta(exp 33)S reservoir must be mass balanced by a complementary negative reservoir.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/618157','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/618157"><span id="translatedtitle">Sulfide isotopic compositions in <span class="hlt">shergottites</span> and ALH84001, and possible implications for life on Mars</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Greenwood, J.P.; McSween, H.Y. Jr.; Riciputi, L.R.</p> <p>1997-10-01</p> <p>The <span class="hlt">shergottite</span> and ALH84001 meteorites hold keys for understanding geologic and possibly biologic processes on Mars. Recently, it has been proposed that carbonates in ALH84001, and the Fe-sulfides they contain, are products of extraterrestrial biogenic activity. Here we report ion microprobe analyses of sulfides in <span class="hlt">shergottites</span> and ALH84001. The sulfur isotope ratios of igneous pyrrhotites in <span class="hlt">shergottites</span> (mean {delta}{sup 34}S{sub CDT}: Shergotty = -0.4{per_thousand}, Zagami = +2.7{per_thousand}, EETA79001A = 1.9{per_thousand}, EETA79001B = -1.7{per_thousand}, LEW88516 = -1.9{per_thousand}, QUE94201 = +0.8{per_thousand}) are similar to those of terrestrial ocean-floor basalts, suggesting that the sulfur isotopic composition of the Martian mantle may be similar to that of the mantle of the Earth. The sulfur isotopic systematics of ALH84001 sulfides are distinct from the <span class="hlt">shergottites</span>. Measured sulfur isotope ratios of eight pyrite grains ({delta}{sup 34}S{sub CDT} = +2.0 to +7.3{per_thousand}) in crushed zones confirm previously reported analyses of isotopically heavy sulfides and are indistinguishable from an Fe-sulfide zone within a carbonate globule ({delta}{sup 34}S{sub CDT} = +6.0{per_thousand}). Analyses of synthesized, fine-grained mixtures of sulfide, carbonate, and magnetite indicate than the measured sulfur isotope ratio is independent of the presence of carbonate and magnetite in the sputtered volume, confirming the accuracy of the analysis of the fine-grained sulfide in the carbonate globule. Terrestrial biogenic sulfate reduction typically results in light isotopic enrichments. The similarity of {delta}{sup 34}S values of the sulfides in ALH84001 imply that the Fe-sulfide zones within ALH84001 carbonates are probably not the result of bacterial reduction of sulfate. 38 refs., 3 figs., 1 tab.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20110012697','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20110012697"><span id="translatedtitle">Stabile Chlorine Isotope Study of Martian <span class="hlt">Shergottites</span> and Nakhlites; Whole Rock and Acid Leachates and Residues</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Nakamura, N.; Nyquist, L. E.; Reese, Y.; Shih, C-Y; Fujitani, T.; Okano, O.</p> <p>2011-01-01</p> <p>We have established a precise analytical technique for stable chlorine isotope measurements of tiny planetary materials by TIMS (Thermal Ionization Mass Spectrometry) [1], for which the results are basically consistent with the IRMS tech-nique (gas source mass spectrometry) [2,3,4]. We present here results for Martian <span class="hlt">shergottites</span> and nakhlites; whole rocks, HNO3-leachates and residues, and discuss the chlorine isotope evolution of planetary Mars.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20140011745','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20140011745"><span id="translatedtitle">Tracking the Martian Mantle Signature in Olivine-Hosted Melt Inclusions of Basaltic <span class="hlt">Shergottites</span> Yamato 980459 and Tissint</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Peters, T. J.; Simon, J. I.; Jones, J. H.; Usui, T.; Moriwaki, R.; Economos, R.; Schmitt, A.; McKeegan, K.</p> <p>2014-01-01</p> <p>The Martian <span class="hlt">shergottite</span> meteorites are basaltic to lherzolitic igneous rocks that represent a period of relatively young mantle melting and volcanism, approximately 600-150 Ma (e.g. [1,2]). Their isotopic and elemental composition has provided important constraints on the accretion, evolution, structure and bulk composition of Mars. Measurements of the radiogenic isotope and trace element concentrations of the <span class="hlt">shergottite</span> meteorite suite have identified two end-members; (1) incompatible trace element enriched, with radiogenic Sr and negative epsilon Nd-143, and (2) incompatible traceelement depleted, with non-radiogenic Sr and positive epsilon 143-Nd(e.g. [3-5]). The depleted component represents the <span class="hlt">shergottite</span> martian mantle. The identity of the enriched component is subject to debate, and has been proposed to be either assimilated ancient martian crust [3] or from enriched domains in the martian mantle that may represent a late-stage magma ocean crystallization residue [4,5]. Olivine-phyric <span class="hlt">shergottites</span> typically have the highest Mg# of the <span class="hlt">shergottite</span> group and represent near-primitive melts having experienced minimal fractional crystallization or crystal accumulation [6]. Olivine-hosted melt inclusions (MI) in these <span class="hlt">shergottites</span> represent the most chemically primitive components available to understand the nature of their source(s), melting processes in the martian mantle, and origin of enriched components. We present trace element compositions of olivine hosted melt inclusions in two depleted olivinephyric <span class="hlt">shergottites</span>, Yamato 980459 (Y98) and Tissint (Fig. 1), and the mesostasis glass of Y98, using Secondary Ionization Mass Spectrometry (SIMS). We discuss our data in the context of understanding the nature and origin of the depleted martian mantle and the emergence of the enriched component.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20070021571','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20070021571"><span id="translatedtitle">Excess Ar-40 in the Zagami <span class="hlt">Shergottite</span>: Does It Reveal Crystallization History?</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Bogard, Donald D.; Park, Jisun</p> <p>2007-01-01</p> <p>The Zagami basaltic <span class="hlt">shergottite</span> has fine- and coarse-grained (FG & CG) areas, which may reflect partial crystallization in a deep, slowly cooled magma chamber to form Mg-rich pyroxene cores, followed by entrainment of these crystals into a magma that rose and crystallized near the surface. Late-stage melt pockets formed mesostasis and feldspar (maskelynite) having a range of compositions, but low water abundance. Higher I(sub Sr) in the FG portion may result from the second stage having incorporated old crustal rocks that failed to reach isotopic equilibrium. Zagami, like other <span class="hlt">shergottites</span>, contains excess Ar-40(sub xs) beyond that expected from internal decay of K-40 during its Sm-Nd age of 177 Myr. We suggest that at least a portion of this Ar-40(sub xs) in Zagami and some other <span class="hlt">shergottites</span> was inherited from the magma, much as is the case of MORBs on Earth. We made Ar-39-Ar-40 age determinations on feldspar and pyroxene separates from both the FG and CG portions of Zagami. If Zagami experienced an evolving fractional crystallization history, including possible crustal contamination of the magma, that might be indicated in differing amounts of Ar-40(sub xs) between mineral phases and between FG and CG portions.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_2");'>2</a></li> <li><a href="#" onclick='return showDiv("page_3");'>3</a></li> <li class="active"><span>4</span></li> <li><a href="#" onclick='return showDiv("page_5");'>5</a></li> <li><a href="#" onclick='return showDiv("page_6");'>6</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_4 --> <div id="page_5" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_3");'>3</a></li> <li><a href="#" onclick='return showDiv("page_4");'>4</a></li> <li class="active"><span>5</span></li> <li><a href="#" onclick='return showDiv("page_6");'>6</a></li> <li><a href="#" onclick='return showDiv("page_7");'>7</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="81"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011M%26PS...46....1Z','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011M%26PS...46....1Z"><span id="translatedtitle">Bounce Rock - A <span class="hlt">shergottite</span>-like basalt encountered at Meridiani Planum, Mars</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Zipfel, Jutta; Schräder, Christian; Jolliff, Bradley L.; Gellert, Ralf; Herkenhoff, Kenneth E.; Rieder, Rudolf; Anderson, Robert; Bell, James F., III; Brückner, Johannes; Crisp, Joy A.; Christensen, Philip R.; Clark, Benton C.; de Souza, Paulo A., Jr.; Dreibus, Gerlind; D'Uston, Claude; Economou, Thanasis; Gorevan, Steven P.; Hahn, Brian C.; Klingelhäfer, Göstar; McCoy, Timothy J.; McSween, Harry Y., Jr.; Ming, Douglas W.; Morris, Richard V.; Rodionov, Daniel S.; Squyres, Steven W.; Wńnke, Heinrich; Wright, Shawn P.; Wyatt, Michael B.; Yen, Albert S.</p> <p>2011-01-01</p> <p>Abstract- The Opportunity rover of the Mars Exploration Rover mission encountered an isolated rock fragment with textural, mineralogical, and chemical properties similar to basaltic <span class="hlt">shergottites</span>. This finding was confirmed by all rover instruments, and a comprehensive study of these results is reported here. Spectra from the miniature thermal emission spectrometer and the Panoramic Camera reveal a pyroxene-rich mineralogy, which is also evident in Mössbauer spectra and in normative mineralogy derived from bulk chemistry measured by the alpha particle X-ray spectrometer. The correspondence of Bounce Rock’s chemical composition with the composition of certain basaltic <span class="hlt">shergottites</span>, especially Elephant Moraine (EET) 79001 lithology B and Queen Alexandra Range (QUE) 94201, is very close, with only Cl, Fe, and Ti exhibiting deviations. Chemical analyses further demonstrate characteristics typical of Mars such as the Fe/Mn ratio and P concentrations. Possible shock features support the idea that Bounce Rock was ejected from an impact crater, most likely in the Meridiani Planum region. Bopolu crater, 19.3 km in diameter, located 75 km to the southwest could be the source crater. To date, no other rocks of this composition have been encountered by any of the rovers on Mars. The finding of Bounce Rock by the Opportunity rover provides further direct evidence for an origin of basaltic <span class="hlt">shergottite</span> meteorites from Mars.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://pubs.er.usgs.gov/publication/70033801','USGSPUBS'); return false;" href="http://pubs.er.usgs.gov/publication/70033801"><span id="translatedtitle">Bounce Rock-A <span class="hlt">shergottite</span>-like basalt encountered at Meridiani Planum, Mars</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Zipfel, J.; Schroder, C.; Jolliff, B.L.; Gellert, Ralf; Herkenhoff, K. E.; Rieder, R.; Anderson, R.; Bell, J.F., III; Brückner, J.; Crisp, J.A.; Christensen, P.R.; Clark, B. C.; de Souza, P.A.; Dreibus, G.; D'uston, C.; Economou, T.; Gorevan, S.P.; Hahn, B.C.; Klingelhofer, G.; McCoy, T.J.; McSween, H.Y.; Ming, D. W.; Morris, R.V.; Rodionov, D.S.; Squyres, S. W.; Wanke, H.; Wright, S.P.; Wyatt, M.B.; Yen, A. S.</p> <p>2011-01-01</p> <p>The Opportunity rover of the Mars Exploration Rover mission encountered an isolated rock fragment with textural, mineralogical, and chemical properties similar to basaltic <span class="hlt">shergottites</span>. This finding was confirmed by all rover instruments, and a comprehensive study of these results is reported here. Spectra from the miniature thermal emission spectrometer and the Panoramic Camera reveal a pyroxene-rich mineralogy, which is also evident in M??ssbauer spectra and in normative mineralogy derived from bulk chemistry measured by the alpha particle X-ray spectrometer. The correspondence of Bounce Rock's chemical composition with the composition of certain basaltic <span class="hlt">shergottites</span>, especially Elephant Moraine (EET) 79001 lithology B and Queen Alexandra Range (QUE) 94201, is very close, with only Cl, Fe, and Ti exhibiting deviations. Chemical analyses further demonstrate characteristics typical of Mars such as the Fe/Mn ratio and P concentrations. Possible shock features support the idea that Bounce Rock was ejected from an impact crater, most likely in the Meridiani Planum region. Bopolu crater, 19.3km in diameter, located 75km to the southwest could be the source crater. To date, no other rocks of this composition have been encountered by any of the rovers on Mars. The finding of Bounce Rock by the Opportunity rover provides further direct evidence for an origin of basaltic <span class="hlt">shergottite</span> meteorites from Mars. ?? The Meteoritical Society, 2011.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19940030961','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19940030961"><span id="translatedtitle">The parent magma of xenoliths in <span class="hlt">shergottite</span> EETA79001: Bulk and trace element composition inferred from magmatic inclusions</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Treiman, Allan H.; Lindstrom, David J.; Martinez, Rene R.</p> <p>1994-01-01</p> <p>The SNC meteorites are samples of the Martian crust, so inferences about their origins and parent magmas are of wide planetologic significance. The EETA79001 <span class="hlt">shergottite</span>, a basalt, contains xenoliths of pyroxene-olivine cumulate rocks which are possibly related to the ALHA77005 and LEW88516 SNC lherzolites. Olivines in the xenoliths contain magmatic inclusions, relics of magma trapped within the growing crystals. The magmatic inclusions allow a parent magma composition to be retrieved; it is similar to the composition reconstructed from xenolith pyroxenes by element distribution coefficients. The xenolith parent magma is similar but not identical to parent magmas for the <span class="hlt">shergottite</span> lherzolites.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013GeCoA.121..546P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013GeCoA.121..546P"><span id="translatedtitle">Ar-Ar ages and trapped Ar components in Martian <span class="hlt">shergottites</span> RBT 04262 and LAR 06319</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Park, Jisun; Bogard, Donald D.; Nyquist, Laurence E.; Garrison, Daniel H.; Mikouchi, Takashi</p> <p>2013-11-01</p> <p>We made 39Ar-40Ar (Ar-Ar) analyses of whole rock (WR) and mineral samples of two Martian <span class="hlt">shergottites</span>, RBT 04262 (RBT) and LAR 06319 (LAR), in order to determine their Ar-Ar ages and the 40Ar/36Ar ratios of the trapped Martian Ar they contain. All samples released trapped (excess) 40Ar and 36Ar and suggested Ar-Ar ages older than their formation ages. Because trapped Ar components having different 40Ar/36Ar were released at different extraction temperatures, we utilized only a portion of the data to derive preferred Ar-Ar ages. We obtain Ar-Ar ages of 171 ± 8 Ma for RBT plagioclase and 163 ± 13 Ma for LAR whole rock. We identify two trapped Ar components. At low temperatures, particularly for plagioclase, Trapped-A with 40Ar/36Ar 285 ± 3 was released, and we believe this is most likely absorbed terrestrial air. At high extraction temperatures, particularly for pyroxene, Trapped-B with 40Ar/36Ar 1813 ± 127 was released. The poikilitic/non-poikilitic texture of RBT and the presence of large pyroxene oikocrysts allowed a clear definition of Trapped-B. This Ar component is Martian, and its isotopic similarity to the Martian atmospheric composition suggests that it may represent Martian atmospheric Ar incorporated into the <span class="hlt">shergottite</span> melt via crustal rocks. Trapped-B partitioned into pyroxene at a constant molar ratio of K/36ArTr = 33.2 ± 9.5 × 106 for RBT 04262, and 80 ± 21 × 106 for LAR 06319. Trapped-A mixed in different proportions with Trapped-B could give apparently intermediate trapped 40Ar/36Ar compositions commonly observed in <span class="hlt">shergottites</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20080009608','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20080009608"><span id="translatedtitle">Petrology and Mineral Chemistry of New Olivine-Phyric <span class="hlt">Shergottite</span> RBT04262</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Dalton, H. A.; Peslier, A. H.; Brandon, A. D.; Lee, C.-T. A.; Lapen, T. J.</p> <p>2008-01-01</p> <p>RBT04262 was found by the 2004-2005 ANSMET team at the Roberts Massif in Antarctica. It is paired with RBT04261 and is classified as an olivine-phyric <span class="hlt">shergottite</span>. RBT04261 is 4.0 x 3.5 x 2.5 cm and 78.8 g, and RBT04262 is 6.5 x 5.5 x 3.5 cm and 204.6 g. Both were partially covered by a fusion crust [1]. Chemical analysis and mapping of this meteorite was performed using the Cameca SX100 electron microprobe at NASA Johnson Space Center.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/1009042','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/1009042"><span id="translatedtitle">Sulfur and iron speciation in gas-rich impact-melt glasses from basaltic <span class="hlt">shergottites</span> determined by microXANES</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Sutton, S.R.; Rao, M.N.; Nyquist, L.E.</p> <p>2008-04-28</p> <p>Sulfur and iron K XANES measurements were made on GRIM glasses from EET 79001. Iron is in the ferrous state. Sulfur speciation is predominately sulfide coordination but is Fe coordinated in Lith B and, most likely, Ca coordinated in Lith A. Sulfur is abundantly present as sulfate near Martian surface based on chemical and mineralogical investigations on soils and rocks in Viking, Pathfinder and MER missions. Jarosite is identified by Moessbauer studies on rocks at Meridian and Gusev, whereas MgSO{sub 4} is deduced from MgO-SO{sub 3} correlations in Pathfinder MER and Viking soils. Other sulfate minerals such as gypsum and alunogen/S-rich aluminosilicates and halides are detected only in martian meteorites such as <span class="hlt">shergottites</span> and nakhlites using SEM/FE-SEM and EMPA techniques. Because sulfur has the capacity to occur in multiple valence states, determination of sulfur speciation (sulfide/sulfate) in secondary mineral assemblages in soils and rocks near Mars surface may help us understand whether the fluid-rock interactions occurred under oxidizing or reducing conditions. On Earth, volcanic rocks contain measurable quantities of sulfur present as both sulfide and sulfate. Carroll and Rutherford showed that oxidized forms of sulfur may comprise a significant fraction of total dissolved sulfur, if the oxidation state is higher than {approx}2 log fO{sub 2} units relative to the QFM buffer. Terrestrial samples containing sulfates up to {approx}25% in fresh basalts from the Galapagos Rift on one hand and high sulfide contents present in oceanic basalts on the other indicate that the relative abundance of sulfide and sulfate varies depending on the oxygen fugacity of the system. Basaltic <span class="hlt">shergottites</span> (bulk) such as Shergotty, EET79001 and Zagami usually contain small amounts of sulfur ({approx}0.5%) as pyrrhotite. But, in isolated glass pockets containing secondary salts (known as GRIM glasses) in these meteorites, sulfur is present in high abundance ({approx}1-12%). To</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011AGUFM.P31B1709S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011AGUFM.P31B1709S"><span id="translatedtitle">EBSD analysis of the <span class="hlt">Shergottite</span> Meteorites: New developments within the technique and their implication on what we know about the preferred orientation of Martian minerals</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Stephen, N.; Benedix, G. K.; Bland, P.; Berlin, J.; Salge, T.; Goran, D.</p> <p>2011-12-01</p> <p>What we know about the geology and mineralogy of the Martian surface has been characterised by both the use of remote sensing techniques and the analysis of Martian meteorites. Various techniques are employed to conduct these analyses including crystallographic, geochemical and spectral measurements, all of which enable us to infer a geological history for these rocks. Several references have been made to the potential for preferred orientation of crystals within the <span class="hlt">Shergottites</span> [1] and their implication for the cooling history of the respective magmas on Mars [2]. We have already shown that a preferred orientation of the two pyroxenes, augite and pigeonite, can be seen in the Zagami meteorite using electron back-scatter diffraction (EBSD) analysis [3]. However, when compared to previous modal studies of the same meteorites [4], it becomes apparent that the current EBSD datasets for Martian meteorites are incomplete. Indexing of some minerals can be hampered by the lack of available matches within library databases for EBSD, or become difficult to resolve between minerals where crystallographic differences between similar minerals fall below the technical limitations of the instrument [3]. Recent advances in EBSD technologies combined with the simultaneous acquisition of energy-dispersive spectra (EDS) however now allow us to determine a more comprehensive set of analyses in a much shorter period of time, fully resolving even similar minerals where areas have been left with no indexing previously [5]. Preliminary investigations suggest that the new technology can successfully index >90% of the sample. The most recent EBSD analyses potentially reveals previously unseen fabrics in the meteorites alongside the EDS hyper-spectral imaging helping to resolve any unknown or questionable phases within them. In this study we will present new data from an investigation using EDS alongside EBSD analysis on 2 <span class="hlt">Shergottite</span> meteorites, SAU 005 and Zagami, to further resolve</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1986GeCoA..50.1031H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1986GeCoA..50.1031H"><span id="translatedtitle">Thermoluminescence and the shock and reheating history of meteorites. III - The <span class="hlt">shergottites</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Hasan, F. A.; Haq, M.; Sears, D. W. G.</p> <p>1986-06-01</p> <p>Thermoluminescence (TL) measurements on Shergotty, ALHA 77005, Zagami, and EETA 79001 (lithology A) have been used to obtain further information on the shock history of these meteorites. The level of TL sensitivity in the <span class="hlt">shergottites</span> varied by a factor of 10, but was always low, probably reflecting the amount of crystalline material in the maskelynite. There are trends in the TL peak temperature, peak width, and TL sensitivity which are believed to be associated with different proportions of feldspar in high- and low-temperature forms. This interpretation is consistent with the observed changes induced in the TL properties by annealing <span class="hlt">shergottites</span> at 400-900 C. It is suggested that the observed trends were produced during postshock crystallization at a variety of cooling rates, the increasing order of cooling rate being EETA 79001, Zagami, ALHA 77005, and Shergotty, and that there is high-temperature feldspar present in all the samples. This implies a postshock temperature above 600 C, and a small (less than 10 m) size of the ejecta. Current theories are well able to explain how objects of this size could have been ejected from Mars.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20150002923','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20150002923"><span id="translatedtitle">Formation and Preservation of the Depleted and Enriched <span class="hlt">Shergottite</span> Isotopic Reservoirs in a Convecting Martian Mantle</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Kiefer, Walter S.; Jones, John H.</p> <p>2015-01-01</p> <p>There is compelling isotopic and crater density evidence for geologically recent volcanism on Mars, in the last 100-200 million years and possibly in the last 50 million years. This volcanism is due to adiabatic decompression melting and thus requires some type of present-day convective upwelling in the martian mantle. On the other hand, martian meteorites preserve evidence for at least 3 distinct radiogenic isotopic reservoirs. Anomalies in short-lived isotopic systems (Sm-146, Nd-142, Hf-182, W-182) require that these reservoirs must have developed in the first 50 to 100 million years of Solar System history. The long-term preservation of chemically distinct reservoirs has sometimes been interpreted as evidence for the absence of mantle convection and convective mixing on Mars for most of martian history, a conclusion which is at odds with the evidence for young volcanism. This apparent paradox can be resolved by recognizing that a variety of processes, including both inefficient mantle mixing and geographic separation of isotopic reservoirs, may preserve isotopic heterogeneity on Mars in an actively convecting mantle. Here, we focus on the formation and preservation of the depleted and enriched isotopic and trace element reservoirs in the <span class="hlt">shergottites</span>. In particular, we explore the possible roles of processes such as chemical diffusion and metasomatism in dikes and magma chambers for creating the isotopically enriched <span class="hlt">shergottites</span>. We also consider processes that may preserve the enriched reservoir against convective mixing for most of martian history.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19860063603&hterms=effect+nuclear&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3Deffect%2Bnuclear','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19860063603&hterms=effect+nuclear&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3Deffect%2Bnuclear"><span id="translatedtitle">Nuclear tracks, Sm isotopes and neutron capture effects in the Elephant Morraine <span class="hlt">shergottite</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Rajan, R. S.; Lugmair, G.; Tamhane, A. S.; Poupeau, G.</p> <p>1986-01-01</p> <p>Nuclear track studies, uranium concentration measurements and Sm-isotope studies have been performed on both lithologies A and B of the Elephant Morraine <span class="hlt">shergottite</span>, EETA 79001. Track studies show that EETA 79001 was a rather small object in space with a preatmospheric radius of 12 + or - 2 cm, corresponding to a preatmospheric mass of 28 + or - 13 kg. Phosphates have U concentrations ranging from 0.3 to 1.3 ppm. There are occasional phosphates with excess fission tracks, possibly produced from neutron-induced fission of U and Th, during the regolith exposure in the <span class="hlt">shergottite</span> parent body (SPB). Sm-isotope studies, while not showing any clear-cut excess in Sm-150, make it possible to derive meaningful upper limits to thermal neutron fluences of 2 to 3 x 10 to the 15th n/sq cm, during a possible regolith irradiation. These limits are consistent with the track data and also make it possible to derive an upper limit to the neutron exposure age of EETA 79001 of 55 Myr in the SPB regolith.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19870046806&hterms=earth+chemical+composition&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3Dearth%2Bchemical%2Bcomposition','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19870046806&hterms=earth+chemical+composition&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3Dearth%2Bchemical%2Bcomposition"><span id="translatedtitle">Core formation in the <span class="hlt">shergottite</span> parent body and comparison with the earth</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Treiman, Allan H.; Jones, John H.; Drake, Michael J.</p> <p>1987-01-01</p> <p>Abundances of elements in <span class="hlt">shergottite</span>, nakhlite, and Chassigny meteorites which originated on a single planet, the <span class="hlt">shergottite</span> parent body (SPB), were examined with the aim of elucidating the chemical conditions of metal separation and core formation in the SPB and of testing present models of planetary core formation. Using partition coefficients and the SPB mantle composition determined in earlier studies, the abundances of Ag, Au, Co, Ga, Mo, Ni, P, Re, S, and W were modeled, with free parameters being oxygen fugacity, proportion of solid metal formed, proportion of metallic liquid formed, and proportion of silicate that is molten. It is shown that the abundances of all elements (except Mo) could be reproduced using models with these four free parameters. In contrast to the SPB, an equivalent model used to predict element abundances in the earth's mantle was shown by Jones and Drake (1986) to be inadequate; there is at present no hypothesis capable of quantitatively reproducing the elemental abundances of the earth's mantle. The contrast suggests that these two terrestrial planets (assuming that the SPB is Mars) may have accreted or differentiated differently.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1986GeCoA..50.1039R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1986GeCoA..50.1039R"><span id="translatedtitle">Nuclear tracks, SM isotopes and neutron capture effects in the Elephant Morraine <span class="hlt">shergottite</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Rajan, R. S.; Lugmair, G.; Tamhane, A. S.; Poupeau, G.</p> <p>1986-06-01</p> <p>Nuclear track studies, uranium concentration measurements and Sm-isotope studies have been performed on both lithologies A and B of the Elephant Morraine <span class="hlt">shergottite</span>, EETA 79001. Track studies show that EETA 79001 was a rather small object in space with a preatmospheric radius of 12 + or - 2 cm, corresponding to a preatmospheric mass of 28 + or - 13 kg. Phosphates have U concentrations ranging from 0.3 to 1.3 ppm. There are occasional phosphates with excess fission tracks, possibly produced from neutron-induced fission of U and Th, during the regolith exposure in the <span class="hlt">shergottite</span> parent body (SPB). Sm-isotope studies, while not showing any clear-cut excess in Sm-150, make it possible to derive meaningful upper limits to thermal neutron fluences of 2 to 3 x 10 to the 15th n/sq cm, during a possible regolith irradiation. These limits are consistent with the track data and also make it possible to derive an upper limit to the neutron exposure age of EETA 79001 of 55 Myr in the SPB regolith.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19860063602&hterms=thermoluminescence&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3Dthermoluminescence','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19860063602&hterms=thermoluminescence&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3Dthermoluminescence"><span id="translatedtitle">Thermoluminescence and the shock and reheating history of meteorites. III - The <span class="hlt">shergottites</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Hasan, F. A.; Haq, M.; Sears, D. W. G.</p> <p>1986-01-01</p> <p>Thermoluminescence (TL) measurements on Shergotty, ALHA 77005, Zagami, and EETA 79001 (lithology A) have been used to obtain further information on the shock history of these meteorites. The level of TL sensitivity in the <span class="hlt">shergottites</span> varied by a factor of 10, but was always low, probably reflecting the amount of crystalline material in the maskelynite. There are trends in the TL peak temperature, peak width, and TL sensitivity which are believed to be associated with different proportions of feldspar in high- and low-temperature forms. This interpretation is consistent with the observed changes induced in the TL properties by annealing <span class="hlt">shergottites</span> at 400-900 C. It is suggested that the observed trends were produced during postshock crystallization at a variety of cooling rates, the increasing order of cooling rate being EETA 79001, Zagami, ALHA 77005, and Shergotty, and that there is high-temperature feldspar present in all the samples. This implies a postshock temperature above 600 C, and a small (less than 10 m) size of the ejecta. Current theories are well able to explain how objects of this size could have been ejected from Mars.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19860034312&hterms=Dunite&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3DDunite','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19860034312&hterms=Dunite&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3DDunite"><span id="translatedtitle">SNC meteorites - Clues to Martian petrologic evolution?. [<span class="hlt">Shergottites</span>, Nakhlites and Chassigny</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Mcsween, H. Y., Jr.</p> <p>1985-01-01</p> <p><span class="hlt">Shergottites</span>, nakhlites and the Chassigny meteorites (SNC group) may have originated on Mars. The <span class="hlt">shergottites</span> are medium-grained basalts, the nakhlites are pyroxenites and the Chassigny is a dunite. The SNC group is petrologically diverse but differs from all other known achondrites in terms of mineral chemistry, the redox state, the oxygen isotopic composition and the radiometric ages. The SNC stones are mafic and ultramafic cumulate rocks with mineralogies that indicate rapid cooling and crystallization from tholeiitic magmas which contained water and experienced a high degree of oxidation. The characteristics suggest formation from a large parent body, i.e., a planet, but not earth. The estimated ages for the rocks match the estimated ages for several mapped Martian volcanoes in the Tharsis region. Additionally, the elemental and isotopic abundances of atmospheric gases embedded in melts in the SNC stones match Viking Lander data for the Martian atmosphere. However, reasons are cited for discounting the possibility that a large meteorite(s) collided with Mars about 180 myr ago and served as the mechanism for ejecting the SNC stones to earth.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20120007400','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20120007400"><span id="translatedtitle">Iron Redox Systematics of <span class="hlt">Shergottites</span> and Martian Magmas</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Righter, Kevin; Danielson, L. R.; Martin, A. M.; Newville, M.; Choi, Y.</p> <p>2010-01-01</p> <p>Martian meteorites record a range of oxygen fugacities from near the IW buffer to above FMQ buffer [1]. In terrestrial magmas, Fe(3+)/ SigmaFe for this fO2 range are between 0 and 0.25 [2]. Such variation will affect the stability of oxides, pyroxenes, and how the melt equilibrates with volatile species. An understanding of the variation of Fe(3+)/SigmaFe for martian magmas is lacking, and previous work has been on FeO-poor and <span class="hlt">Al</span>2O3-rich terrestrial basalts. We have initiated a study of the iron redox systematics of martian magmas to better understand FeO and Fe2O3 stability, the stability of magnetite, and the low Ca/high Ca pyroxene [3] ratios observed at the surface.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012E%26PSL.357..119U','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012E%26PSL.357..119U"><span id="translatedtitle">Origin of water and mantle-crust interactions on Mars inferred from hydrogen isotopes and volatile element abundances of olivine-hosted melt inclusions of primitive <span class="hlt">shergottites</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Usui, Tomohiro; Alexander, Conel M. O'D.; Wang, Jianhua; Simon, Justin I.; Jones, John H.</p> <p>2012-12-01</p> <p>Volatile elements have influenced the differentiation and eruptive behavior of Martian magmas and played an important role in the evolution of Martian climate and near-surface environments. However, the abundances of volatiles, and in particular the amount of water in the Martian interior, are disputed. A record of volatile reservoirs is contained in primitive Martian basalts (<span class="hlt">shergottites</span>). Olivine-hosted melt inclusions from a geochemically depleted <span class="hlt">shergottite</span> (Yamato 980459, representing a very primitive Martian melt) possess undegassed water with a chondritic and Earth-like D/H ratio (δD≤275‰). Based on volatile measurements in these inclusions, the water content of the depleted <span class="hlt">shergottite</span> mantle is calculated to be 15-47 ppm, which is consistent with the dry mantle hypothesis. In contrast to D/H in the depleted <span class="hlt">shergottite</span>, melt from an enriched <span class="hlt">shergottite</span> (Larkman Nunatak 06319), which either formed by melting of an enriched mantle or by assimilation of crust, exhibits an extreme δD of ˜5000‰, indicative of a surface reservoir (e.g., the Martian atmosphere or crustal hydrosphere). These data provide strong evidence that the Martian mantle had retained the primordial low-δD component until at least the time of <span class="hlt">shergottite</span> formation, and that young Martian basalts assimilated old Martian crust.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20140000409','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20140000409"><span id="translatedtitle">Ar-Ar and Rb-Sr Ages of the Tissint Olivine-phyric Martian <span class="hlt">Shergottite</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Park, J.; Herzog, G. F.; Nyquist, L. E.; Shih, C.-Y.; Turin, B.; Lindsay, F. N.; Delaney, J. S.; Swisher, C. C., III; Agee, C.</p> <p>2013-01-01</p> <p>The fifth martian meteorite fall, Tissint, is an olivine-phyric <span class="hlt">shergottite</span> that contains olivine macrocrysts (approximately 1.5 mm) [1]. [2] reported the Sm-Nd age of Tissint as 596 plus or minus 23 Ma along with Rb-Sr data that defined no isochron. [3] reported Lu-Hf and Sm-Nd ages of 583 plus or minus 86 Ma and 616 plus or minus 67 Ma, respectively. The cosmic-ray exposure ages of Tissint are 1.10 plus or minus 0.15 Ma based on 10Be [4], and 1.0-1.1 Ma, based on 3He, 21Ne, and 38Ar [5,6].We report Ar-Ar ages and Rb-Sr data.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010Sci...328..347L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010Sci...328..347L"><span id="translatedtitle">A Younger Age for ALH84001 and Its Geochemical Link to <span class="hlt">Shergottite</span> Sources in Mars</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Lapen, T. J.; Righter, M.; Brandon, A. D.; Debaille, V.; Beard, B. L.; Shafer, J. T.; Peslier, A. H.</p> <p>2010-04-01</p> <p>Martian meteorite ALH84001 (ALH) is the oldest known igneous rock from Mars and has been used to constrain its early history. Lutetium-hafnium (Lu-Hf) isotope data for ALH indicate an igneous age of 4.091 ± 0.030 billion years, nearly coeval with an interval of heavy bombardment and cessation of the martian core dynamo and magnetic field. The calculated Lu/Hf and Sm/Nd (samarium/neodymium) ratios of the ALH parental magma source indicate that it must have undergone extensive igneous processing associated with the crystallization of a deep magma ocean. This same mantle source region also produced the <span class="hlt">shergottite</span> magmas (dated 150 to 570 million years ago), possibly indicating uniform igneous processes in Mars for nearly 4 billion years.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/20395507','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/20395507"><span id="translatedtitle">A younger age for ALH84001 and its geochemical link to <span class="hlt">shergottite</span> sources in Mars.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Lapen, T J; Righter, M; Brandon, A D; Debaille, V; Beard, B L; Shafer, J T; Peslier, A H</p> <p>2010-04-16</p> <p>Martian meteorite ALH84001 (ALH) is the oldest known igneous rock from Mars and has been used to constrain its early history. Lutetium-hafnium (Lu-Hf) isotope data for ALH indicate an igneous age of 4.091 +/- 0.030 billion years, nearly coeval with an interval of heavy bombardment and cessation of the martian core dynamo and magnetic field. The calculated Lu/Hf and Sm/Nd (samarium/neodymium) ratios of the ALH parental magma source indicate that it must have undergone extensive igneous processing associated with the crystallization of a deep magma ocean. This same mantle source region also produced the <span class="hlt">shergottite</span> magmas (dated 150 to 570 million years ago), possibly indicating uniform igneous processes in Mars for nearly 4 billion years. PMID:20395507</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20140012799','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20140012799"><span id="translatedtitle">Preliminary Report on U-Th-Pb Isotope Systematics of the Olivine-Phyric <span class="hlt">Shergottite</span> Tissint</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Moriwaki, R.; Usui, T.; Yokoyama, T.; Simon, J. I.; Jones, J. H.</p> <p>2014-01-01</p> <p>Geochemical studies of <span class="hlt">shergottites</span> suggest that their parental magmas reflect mixtures between at least two distinct geochemical source reservoirs, producing correlations between radiogenic isotope compositions, and trace element abundances.. These correlations have been interpreted as indicating the presence of a reduced, incompatible-element- depleted reservoir and an oxidized, incompatible-element-rich reservoir. The former is clearly a depleted mantle source, but there has been a long debate regarding the origin of the enriched reservoir. Two contrasting models have been proposed regarding the location and mixing process of the two geochemical source reservoirs: (1) assimilation of oxidized crust by mantle derived, reduced magmas, or (2) mixing of two distinct mantle reservoirs during melting. The former clearly requires the ancient martian crust to be the enriched source (crustal assimilation), whereas the latter requires a long-lived enriched mantle domain that probably originated from residual melts formed during solidification of a magma ocean (heterogeneous mantle model). This study conducts Pb isotope and U-Th-Pb concentration analyses of the olivine-phyric <span class="hlt">shergottite</span> Tissint because U-Th-Pb isotope systematics have been intensively used as a powerful radiogenic tracer to characterize old crust/sediment components in mantle- derived, terrestrial oceanic island basalts. The U-Th-Pb analyses are applied to sequential acid leaching fractions obtained from Tissint whole-rock powder in order to search for Pb isotopic source components in Tissint magma. Here we report preliminary results of the U-Th-Pb analyses of acid leachates and a residue, and propose the possibility that Tissint would have experienced minor assimilation of old martian crust.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_3");'>3</a></li> <li><a href="#" onclick='return showDiv("page_4");'>4</a></li> <li class="active"><span>5</span></li> <li><a href="#" onclick='return showDiv("page_6");'>6</a></li> <li><a href="#" onclick='return showDiv("page_7");'>7</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_5 --> <div id="page_6" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_4");'>4</a></li> <li><a href="#" onclick='return showDiv("page_5");'>5</a></li> <li class="active"><span>6</span></li> <li><a href="#" onclick='return showDiv("page_7");'>7</a></li> <li><a href="#" onclick='return showDiv("page_8");'>8</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="101"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19840043311&hterms=Mars+planet&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3DMars%2Bplanet','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19840043311&hterms=Mars+planet&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3DMars%2Bplanet"><span id="translatedtitle">Petrogenesis of the SNC (<span class="hlt">shergottites</span>, nakhlites, chassignites) meteorites - Implications for their origin from a large dynamic planet, possibly Mars</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Smith, M. R.; Laul, J. C.; Ma, M. S.; Huston, T.; Verkouteren, R. M.; Lipschutz, M. E.; Schmitt, R. A.</p> <p>1984-01-01</p> <p>Comprehensive chemical data are presented on the <span class="hlt">shergottites</span> Shergotty, Zagami, Allan Hills (ALHA) 77005, and the new member Elephant Moraine (EETA) 79001 using results of sequential instrumental and radiochemical neutron activation analysis. The close relationship of the Antarctic shergotites indicates that ALHA 77005 is a residual source produced by incongruent melting of a source similar in bulk composition to EETA 79001A and that EETA 79001B and the interstitial phases in EETA 79001A are the melts produced by such melting episodes. The large ion lithophile LIL) trace element abundanced of the <span class="hlt">shergottites</span> require variable but extensive degrees of nomodal melting of isotopically constrained parent sources. The SNG sources are consistent with their derivation by extensive fractionation of a primitive magma initially produced from a source having chondritic refractory LIL trace element abundances. Petrogenetic and age relationships among SNC meteorites suggest a single complex-provenance on a dynamic planet not unlike earth, probably Mars.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20140002468','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20140002468"><span id="translatedtitle">Tracking the Depleted Mantle Signature in Melt Inclusions and Residual Glass of Basaltic Martian <span class="hlt">Shergottites</span> using Secondary Ionization Mass Spectrometry</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Peters, Timothy J.; Simon, Justin I.; Jones, John H.; Usui, Tomohiro; Economos, Rita C.; Schmitt, Axel K.; McKeegan, Kevin D.</p> <p>2013-01-01</p> <p>Trace element abundances of depleted <span class="hlt">shergottite</span> magmas recorded by olivine-hosted melt inclusions (MI) and interstitial mesostasis glass were measured using the Cameca ims-1270 ion microprobe. Two meteorites: Tissint, an olivine-­phyric basaltic <span class="hlt">shergottite</span> which fell over Morocco July 18th 2001; and the Antarctic meteorite Yamato 980459 (Y98), an olivine-phyric basaltic <span class="hlt">shergottite</span> with abundant glassy mesostasis have been studied. Chondrite-­normalized REE patterns for MI in Tissint and Y98 are characteristically LREE depleted and, within analytical uncertainty, parallel those of their respective whole rock composition; supporting each meteorite to represent a melt composition that has experienced closed-­system crystallization. REE profiles for mesostasis glass in Y98 lie about an order of magnitude higher than those from the MI; with REE profiles for Tissint MI falling in between. Y98 MI have the highest average Sm/Nd and Y/Ce ratios, reflecting their LREE depletion and further supporting Y98 as one of our best samples to probe the depleted shergotitte mantle. In general, Zr/Nb ratios overlap between Y98 and Tissint MI, Ce/Nb ratios overlap between Y98 MI and mesostasis glass, and Sm/Nd ratios overlap between Y98 mesostasis glass and Tissint MI. These features support similar sources for both, but with subtle geochemical differences that may reflect different melting conditions or fractionation paths during ascent from the mantle. Interestingly, the REE patterns for both Y98 bulk and MI analyses display a flattening of the LREE that suggests a crustal contribution to the Y98 parent melt. This observation has important implications for the origins of depleted and enriched <span class="hlt">shergottites</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20140012817','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20140012817"><span id="translatedtitle">Identification of Martian Regolith Sulfur Components in <span class="hlt">Shergottites</span> Using Sulfur K Xanes and Fe/S Ratios</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Sutton, S. R.; Ross, D. K.; Rao, M. N.; Nyquist, L. E.</p> <p>2014-01-01</p> <p>Based on isotopic anomalies in Kr and Sm, Sr-isotopes, S-isotopes, XANES results on S-speciation, Fe/S ratios in sulfide immiscible melts [5], and major element correlations with S determined in impact glasses in EET79001 Lith A & Lith B and Tissint, we have provided very strong evidence for the occurrence of a Martian regolith component in some impact melt glasses in <span class="hlt">shergottites</span>. Using REE measurements by LA-ICP-MS in <span class="hlt">shergottite</span> impact glasses, Barrat and co-workers have recently reported conflicting conclusions about the occurrence of Martian regolith components: (a) Positive evidence was reported for a Tissint impact melt, but (b) Negative evidence for impact melt in EET79001 and another impact melt in Tissint. Here, we address some specific issues related to sulfur speciation and their relevance to identifying Martian regolith components in impact glasses in EET79001 and Tissint using sulfur K XANES and Fe/S ratios in sulfide immiscible melts. XANES and FE-SEM measurements in approx. 5 micron size individual sulfur blebs in EET79001 and Tissint glasses are carried out by us using sub-micron size beams, whereas Barrat and coworkers used approx. 90 micron size laser spots for LA- ICP-MS to determine REE abundances in bulk samples of the impact melt glasses. We contend that Martian regolith components in some <span class="hlt">shergottite</span> impact glasses are present locally, and that studying impact melts in various <span class="hlt">shergottites</span> can give evidence both for and against regolith components because of sample heterogeneity.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016M%26PS..tmp..325F','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016M%26PS..tmp..325F"><span id="translatedtitle">Effect of chlorine on near-liquidus crystallization of olivine-phyric <span class="hlt">shergottite</span> NWA 6234 at 1 GPa: Implication for volatile-induced melting of the Martian mantle</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Farcy, Benjamin J.; Gross, Juliane; Carpenter, Paul; Hicks, Jacob; Filiberto, Justin</p> <p>2016-05-01</p> <p>Martian magmas are thought to be rich in chlorine compared with their terrestrial counterparts. Here, we experimentally investigate the effect of chlorine on liquidus depression and near-liquidus crystallization of olivine-phyric <span class="hlt">shergottite</span> NWA 6234 and compare these results with previous experimental results on the effect of chlorine on near-liquidus crystallization of the surface basalts Humphrey and Fastball. Previous experimental results showed that the change in liquidus temperature is dependent on the bulk composition of the basalt. The effect of chlorine on liquidus depression is greater for lower SiO2 and higher <span class="hlt">Al</span>2O3 magmas than for higher SiO2 and lower <span class="hlt">Al</span>2O3 magmas. The bulk composition for this study has lower <span class="hlt">Al</span>2O3 and higher FeO contents than previous work; therefore, we provide additional constraints on the effect of the bulk composition on the influence of chlorine on near-liquidus crystallization. High pressure and temperature crystallization experiments were performed at 1 GPa on a synthetic basalt, of the bulk composition of NWA 6234, with 0-4 wt% Cl added to the sample as AgCl. The results are consistent with previous notions that with increasing wt% Cl in the melt, the crystallization temperature decreases. Importantly, our results have a liquidus depression ∆T (°C) from added chlorine that is consistent with the difference in bulk composition and suggest a dependence on both the bulk <span class="hlt">Al</span>2O3 and FeO content. Our results suggest that the addition of chlorine to the Martian mantle may lower magma genesis temperatures and potentially aid in the petrogenesis of Martian magmas.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2009AGUFMMR12A..03E','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2009AGUFMMR12A..03E"><span id="translatedtitle">Shock-Induced Melting of Maskelynite and the High-pressure Mineral Inventory of <span class="hlt">Shergottites</span>: Implications to Evaluation of the Shock History of Martian Meteorites</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>El Goresy, A.</p> <p>2009-12-01</p> <p>Maskelynite [1-2] and the shock-induced melt pockets in <span class="hlt">shergottites</span> are diagnostic features evidencing a major dynamic event on their parent body, Mars. Several models have been proposed for the origin of maskelynite: shock-induced solid-state vitrification of labradorite [3-4], metastable melting and quenching at high-pressure (high-P) [5], or ductile mobilization [4, 6]. Similarly, the origin and relevance of shock-melt pockets and veins as the main locations of high-P minerals in <span class="hlt">shergottites</span> are controversial: localized formation by P-temperature (T) spikes in excess of 70-80 GPa [3, 4] or equilibrium assemblages evidencing peak-shock-P in the range of 25-35 GPa are discussed [7-10]. Crystallization ages are also controversial, with peaks at 160-190 Ma [11] and ≥ 4.1 Ga [12]: shock-induced age resetting may have been misinterpreted as igneous ages. We present ample evidence that maskelynite formed by metastable melting of plagioclase and quenching to glass at high-pressures as a result of the sluggishness of its inversion to lingunite. The direct consequence of our findings is the irrelevance of the refractive indices (RIs) of maskelynite as pressure indicators [3-4], since RIs were first established after decompression and quenching of maskelynite at its closure temperature of relaxation. We investigated the phase assemblages in Shergotty, Zagami, DAG 476, SAU 005, NWA 480, and NWA 856. Maskelynite contains the dense silica polymorph seifertite and the very dense monoclinic polymorph [8 -10]. Lingunite, CAS polymorph and Stishovite are present in shock-melt pockets [7-10]. Akimotoite, and silicate titanite were reported in shock-melt veins [13, 14]. The silicate liquids in which these dense minerals crystallized were perfect P-transmitting media, hence, contrary to [3-4], the dense minerals formed in equilibrium. The shock-induced events could be sequentially delineated commencing with the solid-state inversion to seifertite followed by pervasive melting of</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20150001926','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20150001926"><span id="translatedtitle">Mineralogical Comparison of Olivine in <span class="hlt">Shergottites</span> and A Shocked L Chondrite: Implications for Shock Histories of Brown Olivine</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Takenouchi, A.; Mikouchi, T.; Yamaguchi, A.; Zolensky, M. E.</p> <p>2015-01-01</p> <p>Most Martian meteorites are heavily shocked, exhibiting numerous shock features, for example undulatory extinction of olivine and pyroxene, the presence of diaplectic glass ("maskelynite") and the formation of shock melt. Among these shock features, olivine darkening ("brown" olivine) is unique in Martian meteorites because no other meteorite group shows such a feature. Although the presence of brown olivine in <span class="hlt">shergottites</span> was reported thirty years ago, detailed observation by TEM has not been performed until the NWA 2737 chassignite was discovered, whose olivine is darkened, being completely black in hand specimen. Fe metal nano-particles were found in NWA 2737 olivine which are considered to have been formed by olivine reduction during heavy shock. Subsequently, magnetite nano-particles were also found in other Martian meteorites and the coexistence of Fe metal and magnetite nano-particles was reported in the NWA 1950 <span class="hlt">shergottite</span> and some Fe metal nano-particles were mantled by magnetite. Therefore, the formation process of nano-particles seems to be complex. Because "brown" olivine is unique to Martian meteorites, they have a potential to constrain their shock conditions. In order to better understand the shock history of Martian meteorites, we compared olivine in several <span class="hlt">shergottites</span> with that in a highly-shocked L chondrite which contains ringwoodite.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016M%26PS..tmp..324F','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016M%26PS..tmp..324F"><span id="translatedtitle">Igneous cooling history of olivine-phyric <span class="hlt">shergottite</span> Yamato 980459 constrained by dynamic crystallization experiments</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>First, Emily; Hammer, Julia</p> <p>2016-05-01</p> <p>Dynamic crystallization experiments were performed on a liquid having the bulk composition of olivine-phyric <span class="hlt">shergottite</span> Yamato 980459, to constrain the igneous thermal history of this meteorite. Key characteristics of the meteorite's mineralogy and texture, including several morphologically distinct olivine and pyroxene crystal populations and a glassy mesostasis devoid of plagioclase, were replicated upon cooling from 1435 to 909 °C at 1 atmosphere under reducing conditions. Three sequential cooling ramps are required to produce synthetic samples with textures and compositions matching Yamato 980459. Olivine phenocrysts formed at <1 °C h-1, presumably at depth in the Martian crust. Pyroxene phenocrysts formed mainly at ~10 °C h-1, consistent with crystallization within a lava flow at depths of 25-45 cm. Increased cooling rate (~100 °C h-1) in a third stage suppressed the formation of plagioclase and produced groundmass crystals, consistent with crystallization at lava flow depths of 5-7 cm. Although Y 980459 is unique among Martian meteorites (i.e., preserving a primary glassy mesostasis), its emplacement did not require unique physical conditions. Rather, the second and third cooling stages may reflect cooling within the core of a pāhoehoe-like flow and subsequent breakout on the surface of Mars.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2016M%26PS..tmp..287H&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2016M%26PS..tmp..287H&link_type=ABSTRACT"><span id="translatedtitle">Postcrystallization metasomatism in <span class="hlt">shergottites</span>: Evidence from the paired meteorites LAR 06319 and LAR 12011</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Howarth, Geoffrey H.; Liu, Yang; Chen, Yang; Pernet-Fisher, John F.; Taylor, Lawrence A.</p> <p>2016-03-01</p> <p>Apatite is the major volatile-bearing phase in Martian meteorites, containing structurally bound fluorine, chlorine, and hydroxyl ions. In apatite, F is more compatible than Cl, which in turn is more compatible than OH. During degassing, Cl strongly partitions into the exsolved phase, whereas F remains in the melt. For these reasons, the volatile concentrations within apatite are predictable during magmatic differentiation and degassing. Here, we present compositional data for apatite and merrillite in the paired enriched, olivine-phyric <span class="hlt">shergottites</span> LAR 12011 and LAR 06319. In addition, we calculate the relative volatile fugacities of the parental melts at the time of apatite formation. The apatites are dominantly OH-rich (calculated by stoichiometry) with variable yet high Cl contents. Although several other studies have found evidence for degassing in the late-stage mineral assemblage of LAR 06319, the apatite evolutionary trends cannot be reconciled with this interpretation. The variable Cl contents and high OH contents measured in apatites are not consistent with fractionation either. Volatile fugacity calculations indicate that water and fluorine activities remain relatively constant, whereas there is a large variation in the chlorine activity. The Martian crust is Cl-rich indicating that changes in Cl contents in the apatites may be related to an external crustal source. We suggest that the high and variable Cl contents and high OH contents of the apatite are the results of postcrystallization interaction with Cl-rich, and possibly water-rich, crustal fluids circulating in the Martian crust.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19950047179&hterms=gases+combustion&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D90%26Ntt%3Dgases%2Bcombustion','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19950047179&hterms=gases+combustion&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D90%26Ntt%3Dgases%2Bcombustion"><span id="translatedtitle">Nitrogen and noble gases in a glass sample from the LEW88516 <span class="hlt">shergottite</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Becker, Richard H.; Pepin, Robert O.</p> <p>1993-01-01</p> <p>A glass separate from the LEW88516 <span class="hlt">shergottite</span> was analyzed by step-wise combustion for N and noble gases to determine whether it contained trapped gas similar in composition to the martian atmosphere-like component previously observed in lithology C of EETA79001. Excesses of Ar-40 and Xe-129 were in fact observed in this glass, although the amounts of these excesses less than or = to 20% of those seen in the latter meteorite, and are comparable to the amounts seen in whole-rock analyses of LEW88516. The isotopic composition of N in LEW88516 does not show an enrichment in delta N-15 commensurate with the amount of isotopically-heavy N expected from the noble gases excesses. One must posit some extreme assumptions about the nature of the N components present in LEW88516 in order to allow the presence of the trapped nitrogen component. Alternatively, the N has somehow been decoupled from the noble gases, and was either never present of has been lost.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2016M%26PS...51.1233F&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2016M%26PS...51.1233F&link_type=ABSTRACT"><span id="translatedtitle">Igneous cooling history of olivine-phyric <span class="hlt">shergottite</span> Yamato 980459 constrained by dynamic crystallization experiments</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>First, Emily; Hammer, Julia</p> <p>2016-07-01</p> <p>Dynamic crystallization experiments were performed on a liquid having the bulk composition of olivine-phyric <span class="hlt">shergottite</span> Yamato 980459, to constrain the igneous thermal history of this meteorite. Key characteristics of the meteorite's mineralogy and texture, including several morphologically distinct olivine and pyroxene crystal populations and a glassy mesostasis devoid of plagioclase, were replicated upon cooling from 1435 to 909 °C at 1 atmosphere under reducing conditions. Three sequential cooling ramps are required to produce synthetic samples with textures and compositions matching Yamato 980459. Olivine phenocrysts formed at <1 °C h-1, presumably at depth in the Martian crust. Pyroxene phenocrysts formed mainly at ~10 °C h-1, consistent with crystallization within a lava flow at depths of 25-45 cm. Increased cooling rate (~100 °C h-1) in a third stage suppressed the formation of plagioclase and produced groundmass crystals, consistent with crystallization at lava flow depths of 5-7 cm. Although Y 980459 is unique among Martian meteorites (i.e., preserving a primary glassy mesostasis), its emplacement did not require unique physical conditions. Rather, the second and third cooling stages may reflect cooling within the core of a pāhoehoe-like flow and subsequent breakout on the surface of Mars.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20050167804','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20050167804"><span id="translatedtitle">Experimental Petrology of the Basaltic <span class="hlt">Shergottite</span> Yamato 980459: Implications for the Thermal Structure of the Martian Mantle</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Dalton, H. A.; Musselwhite, D. S.; Kiefer, W.; Treiman, A. H.</p> <p>2005-01-01</p> <p>Yamato 980459 (Y98) is an olivine-phyric basaltic <span class="hlt">shergottite</span> composed of 48% pyroxene, 26% olivine, 25% mesostasis, and 1% other minerals. Unlike the other Martian basalts, it contains no plagioclase. Olivine in Y98 is the most magnesian of all Martian meteorites. Thus Y98 is believed to be the most primitive and its composition may be the closest to a primary or direct melt of the Martian mantle. As such, it provides a very useful probe of the mineralogy and depth of its mantle source region. Toward this end, we are conducting crystallization experiments on a synthetic Y98 composition at Martian mantle pressures and temperatures.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20110007805','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20110007805"><span id="translatedtitle">Recognizing the Effects of Terrestrial Contamination on D/H Ratios in <span class="hlt">Shergottite</span> Phosphates</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Ross, D. K.; Ito, M.; Hervig, R.; Rao, M. N.; Nyquist, L. E.</p> <p>2011-01-01</p> <p>Hydrogen isotope ratios in <span class="hlt">shergottite</span> phosphate minerals have been investigated by SIMS in the meteorites Queen Alexandra Range (QUE) 94201 and Los Angeles. We have also collected electron probe data on these phosphates in order to characterize the phosphate minerals and attempt to document any potential hydrogen isotopic differences between chlor-apatite and whitlockite. In the section of Los Angeles we studied (748), we found both chlor-apatite and whitlockite, but in the section of QUE 94201,38 studied, we found only whitlockite. In both meteorites, D/H ratios (expressed in units of delta D (sub SMOW) vary, from terrestrial values up to approximately 5400%o in QUE 94201, and to approximately 3800%o in Los Angeles. We have carefully examined the ion probed pits with high-resolution FE-SEM. In most cases where the D/H ratios are low, we have iden-tified cracks that instersect the ion probe pit. These cracks are not visible in the optical microscope attached to the SIMS instument, making them impossible to avoid during SIMS data collection. We contend that the low ratios are a function of substantial terrestrial contamination, and that similar contamination is a likely factor in previously published studies on D/H ratios in martian phosphates. Here we highlight the difficulty of attempts to constrain the martian mantle D/H ratio using phosphate data, given that both terrestrial contamination and martian mantle hydrogen will move phosphate D/H ratios in the same direction, toward lower values. We note that our data include some of the most deuterium-rich values ever reported for martian phosphates. It is clear that some of our measurements are only minimally or totally uncontaminated, but the question arises, are intermediate values diminished because of true martian variability, or do they reflect contamination?</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20130011096','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20130011096"><span id="translatedtitle">Compositions of Magmatic and Impact Melt Sulfides in Tissint And EETA79001: Precursors of Immiscible Sulfide Melt Blebs in <span class="hlt">Shergottite</span> Impact Melts</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Ross, D. K.; Rao, M. N.; Nyquist, L.; Agee, C.; Sutton, S.</p> <p>2013-01-01</p> <p>Immiscible sulfide melt spherules are locally very abundant in <span class="hlt">shergottite</span> impact melts. These melts can also contain samples of Martian atmospheric gases [1], and cosmogenic nuclides [2] that are present in impact melt, but not in the host <span class="hlt">shergottite</span>, indicating some components in the melt resided at the Martian surface. These observations show that some regolith components are, at least locally, present in the impact melts. This view also suggests that one source of the over-abundant sulfur in these impact melts could be sulfates that are major constituents of Martian regolith, and that the sulfates were reduced during shock heating to sulfide. An alternative view is that sulfide spherules in impact melts are produced solely by melting the crystalline sulfide minerals (dominantly pyrrhotite, Fe(1-x)S) that are present in <span class="hlt">shergottites</span> [3]. In this abstract we report new analyses of the compositions of sulfide immiscible melt spherules and pyrrhotite in the <span class="hlt">shergottites</span> Tissint, and EETA79001,507, and we use these data to investigate the possible origins of the immiscible sulfide melt spherules. In particular, we use the metal/S ratios determined in these blebs as potential diagnostic criteria for tracking the source material from which the numerous sulfide blebs were generated by shock in these melts.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=20020046467&hterms=Gadolinium&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D60%26Ntt%3DGadolinium','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=20020046467&hterms=Gadolinium&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D60%26Ntt%3DGadolinium"><span id="translatedtitle">An Experimental Study of Eu/Gd Partitioning Between a <span class="hlt">Shergottite</span> Melt and Pigeonite: Implications for the Oxygen Fugacity of the Martian Interior</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>McCanta, M. C.; Rutherford, M. J.; Jones, J. H.</p> <p>2002-01-01</p> <p>We experimentally investigated the partitioning behavior of Eu/Gd between a synthetic <span class="hlt">shergottite</span> melt and pigeonite as a function of oxygen fugacity. This has implications for the oxidation state of the source region of the martian meteorites. Additional information is contained in the original extended abstract.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013GeCoA.108....1L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013GeCoA.108....1L"><span id="translatedtitle">New constraints on the formation of <span class="hlt">shergottite</span> Elephant Moraine 79001 lithology A</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Liu, Yang; Balta, J. Brian; Goodrich, Cyrena A.; McSween, Harry Y.; Taylor, Lawrence A.</p> <p>2013-05-01</p> <p>Previous studies of Elephant Moraine (EET) 79001 disagreed upon the nature of the magnesian olivine and orthopyroxene grains, and generally considered the formation of EET 79001 at low pressure conditions. New observations on mineral associations, and trace-element abundances of olivine-hosted melt inclusions, in lithology A (EET-A) of EET 79001 lead to new constraints on the formation of this meteorite. The abundances and chondrite-normalized REE pattern of the average melt inclusions in olivine of Mg# 75-61 are similar to those of the bulk-rock composition of lithology A, suggesting that the Mg# <77 olivines are phenocrysts. We also report the widespread occurrence of round orthopyroxene (En78.9-77.9Wo2.2-2.5) inclusions in disequilibrium contact with their olivine hosts (Mg# 73-68). Compositions of these inclusions are similar to xenocrystic cores (Mg# ⩾77; Wo ⩽4) in pyroxene megacrysts. These observations indicate that orthopyroxene xenocrysts were being resorbed while Mg# 77-73 olivine was crystallizing. Combined, these observations suggest that only small portions of the megacrysts are xenocrystic, namely orthopyroxene of Mg# ⩾77 and Wo ⩽4, and possibly also olivine of Mg# ⩾77. The volume percentages of the xenocrystic materials in the rock are small (⩽1 vol.% for each mineral). Compositions of the xenocrystic minerals are similar to cores of megacrysts in olivine-phyric <span class="hlt">shergottite</span> Yamato (Y) 980459 and Northwest Africa (NWA) 5789. Considering the small fraction of xenocrysts and the similarity between REE abundances of the early-trapped melt and those in bulk EET-A, we re-evaluated the possibility that the bulk-rock composition of EET-A is close to that of its parent melt. Results of pMELTS modeling indicate that polybaric crystallization of the EET-A bulk composition (corrected by removal of xenocryst material) can reproduce the crystallization sequence of EET-A, in contrast to the conclusions of previous workers. We estimate that the EET</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011AGUFMEP41A0577S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011AGUFMEP41A0577S"><span id="translatedtitle">Intensity normalization and automatic gain control correction of airborne Li<span class="hlt">DAR</span> data for classifying a rangeland ecosystem</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Shrestha, R.; Glenn, N. F.; Spaete, L.; Mitchell, J.</p> <p>2011-12-01</p> <p>Airborne Li<span class="hlt">DAR</span> not only records elevation but also the intensity, or the amplitude, of the returning light beam. Li<span class="hlt">DAR</span> intensity information can be useful for many applications, including landcover classification. Intensity is directly associated with the reflectance of the target surface and can be influenced by factors such as flying altitude and sensor settings. Li<span class="hlt">DAR</span> intensity data must be calibrated before use and this is especially important for multi-temporal studies where differing flight conditions can cause more variations. Some sensors such as the Leica <span class="hlt">ALS</span>50 Phase II also records automatic gain control (AGC), which controls the gain of the Li<span class="hlt">DAR</span> signal, allowing information from low-reflectance surfaces. We demonstrate a post-processing method for calibrating intensity using airborne Li<span class="hlt">DAR</span> data collected over a sage-steppe ecosystem in southeastern Idaho, USA. Range normalization with respect to the sensor-to-object distance is performed by using smoothed best estimated trajectory information collected at an interval of every second. Optimal parameters for calibrating AGC data are determined by collecting spectral reference data at the time of overflights, in test areas with homogenous backscatter properties. Intensity calibration results are compared with vendor corrected intensity data, and used to perform landcover classification using the Random Forests method. We also test this intensity calibration approach using a separate multi-temporal Li<span class="hlt">DAR</span> data set collected by the same sensor.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2009GeCoA..73.3471B&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2009GeCoA..73.3471B&link_type=ABSTRACT"><span id="translatedtitle">Experimental study of polybaric REE partitioning between olivine, pyroxene and melt of the Yamato 980459 composition: Insights into the petrogenesis of depleted <span class="hlt">shergottites</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Blinova, Alexandra; Herd, Christopher D. K.</p> <p>2009-06-01</p> <p>A synthetic composition representing the Yamato 980459 martian basalt (<span class="hlt">shergottite</span>) has been used to carry out phase relation, and rare earth element (REE) olivine and pyroxene partitioning experiments. Yamato 980459 is a sample of primitive basalt derived from a reduced end-member among martian mantle sources. Experiments carried out between 1-2 GPa and 1350-1650 °C simulate the estimated pressure-temperature conditions of basaltic melt generation in the martian mantle. Olivine-melt and orthopyroxene-melt partition coefficients for La, Nd, Sm, Eu, Gd and Yb ( DREE values) were determined by LA-ICPMS, and are similar to the published values for terrestrial basaltic systems. We have not detected significant variation in D-values with pressure over the range investigated, and by comparison with previous studies carried out at lower pressure. We apply the experimentally obtained olivine-melt and orthopyroxene-melt DREE values to fractional crystallization and partial melting models to develop a three-stage geochemical model for the evolution of martian meteorites. In our model we propose two ancient (˜4.535 Ga) sources: the Nakhlite Source, located in the shallow mantle, and the Deep Mantle Source, located close to the martian core-mantle boundary. These two sources evolved distinctly on the ɛ 143Nd evolution curve due to their different Sm/Nd ratios. By partially melting the Nakhlite Source at ˜1.3 Ga, we are able to produce a slightly depleted residue (Nakhlite Residue). The Nakhlite Residue is left undisturbed until ˜500 Ma, at which point the depleted Deep Mantle Source is brought up by a plume mechanism carrying with it high heat flow, melts and isotopic signatures of the deep mantle (e.g., ɛ 182W, ɛ 142Nd, etc.). The plume-derived Deep Mantle Source combines with the Nakhlite Residue producing a mixture that becomes a mantle source (herein referred to as "the Y98 source") for Yamato 980459 and the other depleted <span class="hlt">shergottites</span> with the characteristic range</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19910025973&hterms=Cerium&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D60%26Ntt%3DCerium','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19910025973&hterms=Cerium&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D60%26Ntt%3DCerium"><span id="translatedtitle">Rare earth elements in minerals of the ALHA77005 <span class="hlt">shergottite</span> and implications for its parent magma and crystallization history</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Lundberg, Laura L.; Crozaz, Ghislaine; Mcsween, Harry Y., Jr.</p> <p>1990-01-01</p> <p>Analyses of mineral REE and selected minor and trace elements were carried out on individual grains of pyroxenes, whitlockite, maskelynite, and olivine of the Antarctic <span class="hlt">shergottite</span> ALHA77005, and the results are used to interpret its parent magma and crystallization history. The results of mineral compositions and textural observations suggest that ALHA77005 is a cumulate with about half cumulus material (olivine + chromite) and half postcumulus phases. Most of the REEs in ALHA77005 reside in whitlockite whose modal concentration is about 1 percent. Mineral REE data support previous suggestions that plagioclase and whitlockite crystallized late, and that low-Ca pyroxene initiated crystallization before high-Ca pyroxene. The REE patterns for the intercumulus liquid, calculated from distribution coefficients for ALHA77005 pyroxene, plagioclase, and whitlockite, are in very good agreement and are similar to that of Shergotty.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20070009871','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20070009871"><span id="translatedtitle">Lu-Hf and Sm-Nd Isotopic Studies of <span class="hlt">Shergottites</span> and Nakhlites: Implications for Martian Mantle Sources</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Debaille, V.; Yin, Q.-Z.; Brandon, A. D.; Jacobsen, B.; Treiman, A. H.</p> <p>2007-01-01</p> <p>We present a new Lu-Hf and Sm-Nd isotope systematics study of four enriched <span class="hlt">shergottites</span> (Zagami, Shergotty, NWA856 and Los Angeles), and three nakhlites (Nakhla, MIL03346 and Yamato 000593) in order to further understand processes occurring during the early differentiation of Mars and the crystallization of its magma ocean. Two fractions of the terrestrial petrological analogue of nakhlites, the Archaean Theo's flow (Ontario, Canada) were also measured. The coupling of Nd and Hf isotopes provide direct insights on the mineralogy of the melt sources. In contrast to Sm/Nd, Lu/Hf ratios can be very large in minerals such as garnet. Selective partial melting of garnet bearing mantle sources can therefore lead to characteristic Lu/Hf signatures that can be recognized with Hf-176/Hf-177Hf ratios.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010AGUFM.B33A0387R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010AGUFM.B33A0387R"><span id="translatedtitle">Modelling Sensor and Target effects on Li<span class="hlt">DAR</span> Waveforms</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Rosette, J.; North, P. R.; Rubio, J.; Cook, B. D.; Suárez, J.</p> <p>2010-12-01</p> <p>The aim of this research is to explore the influence of sensor characteristics and interactions with vegetation and terrain properties on the estimation of vegetation parameters from Li<span class="hlt">DAR</span> waveforms. This is carried out using waveform simulations produced by the FLIGHT radiative transfer model which is based on Monte Carlo simulation of photon transport (North, 1996; North et <span class="hlt">al</span>., 2010). The opportunities for vegetation analysis that are offered by Li<span class="hlt">DAR</span> modelling are also demonstrated by other authors e.g. Sun and Ranson, 2000; Ni-Meister et <span class="hlt">al</span>., 2001. Simulations from the FLIGHT model were driven using reflectance and transmittance properties collected from the Howland Research Forest, Maine, USA in 2003 together with a tree list for a 200m x 150m area. This was generated using field measurements of location, species and diameter at breast height. Tree height and crown dimensions of individual trees were calculated using relationships established with a competition index determined for this site. Waveforms obtained by the Laser Vegetation Imaging Sensor (LVIS) were used as validation of simulations. This provided a base from which factors such as slope, laser incidence angle and pulse width could be varied. This has enabled the effect of instrument design and laser interactions with different surface characteristics to be tested. As such, waveform simulation is relevant for the development of future satellite Li<span class="hlt">DAR</span> sensors, such as NASA’s forthcoming DESDynI mission (NASA, 2010), which aim to improve capabilities of vegetation parameter estimation. ACKNOWLEDGMENTS We would like to thank scientists at the Biospheric Sciences Branch of NASA Goddard Space Flight Center, in particular to Jon Ranson and Bryan Blair. This work forms part of research funded by the NASA DESDynI project and the UK Natural Environment Research Council (NE/F021437/1). REFERENCES NASA, 2010, DESDynI: Deformation, Ecosystem Structure and Dynamics of Ice. http</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_4");'>4</a></li> <li><a href="#" onclick='return showDiv("page_5");'>5</a></li> <li class="active"><span>6</span></li> <li><a href="#" onclick='return showDiv("page_7");'>7</a></li> <li><a href="#" onclick='return showDiv("page_8");'>8</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_6 --> <div id="page_7" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_5");'>5</a></li> <li><a href="#" onclick='return showDiv("page_6");'>6</a></li> <li class="active"><span>7</span></li> <li><a href="#" onclick='return showDiv("page_8");'>8</a></li> <li><a href="#" onclick='return showDiv("page_9");'>9</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="121"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2012E%26PSL.341..195N&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2012E%26PSL.341..195N&link_type=ABSTRACT"><span id="translatedtitle">U-Pb isotopic systematics of shock-loaded and annealed baddeleyite: Implications for crystallization ages of Martian meteorite <span class="hlt">shergottites</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Niihara, Takafumi; Kaiden, Hiroshi; Misawa, Keiji; Sekine, Toshimori; Mikouchi, Takashi</p> <p>2012-08-01</p> <p>Shock-recovery and annealing experiments on basalt-baddeleyite mixtures were undertaken to evaluate shock effects on U-Pb isotopic systematics of baddeleyite. Shock pressures up to 57 GPa caused fracturing of constituent phases, mosaicism of olivine, maskelynitization of plagioclase, and melting, but the phase transition from monoclinic baddeleyite structure to high-pressure/temperature polymorphs of ZrO2 was not confirmed. The U-Pb isotopic systems of the shock-loaded baddeleyite did not show a large-scale isotopic disturbance. The samples shock-recovered from 47 GPa were then employed for annealing experiments at 1000 or 1300 °C, indicating that the basalt-baddeleyite mixture was almost totally melted except olivine and baddeleyite. Fine-grained euhedral zircon crystallized from the melt was observed around the relict baddeleyite in the sample annealed at 1300 °C for 1 h. The U-Pb isotopic systems of baddeleyite showed isotopic disturbances: many data points for the samples annealed at 1000 °C plotted above the concordia. Both radiogenic lead loss/uranium gain and radiogenic lead gain/uranium loss were observed in the baddeleyite annealed at 1300 °C. Complete radiogenic lead loss due to shock metamorphism and subsequent annealing was not observed in the shock-loaded/annealed baddeleyites studied here. These results confirm that the U-Pb isotopic systematics of baddeleyite are durable for shock metamorphism. Since <span class="hlt">shergottites</span> still preserve Fe-Mg and/or Ca zonings in major constituent phases (i.e. pyroxene and olivine), the shock effects observed in Martian baddeleyites seem to be less intense compared to that under the present experimental conditions. An implication is that the U-Pb systems of baddeleyite in <span class="hlt">shergottites</span> will provide crystallization ages of Martian magmatic rocks.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19860063595&hterms=Igneous+rocks&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D90%26Ntt%3D%2528Igneous%2Brocks%2529','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19860063595&hterms=Igneous+rocks&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D90%26Ntt%3D%2528Igneous%2Brocks%2529"><span id="translatedtitle">A discussion of isotopic systematics and mineral zoning in the <span class="hlt">shergottites</span> - Evidence for a 180 m.y. igneous crystallization age</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Jones, J. H.</p> <p>1986-01-01</p> <p>The chronologies of the Shergotty, Zagami, ALHA 77005, and EETA 79001 meteorites were reexamined on the basis of <span class="hlt">shergottites</span>' petrography and mineral chemistry data. Among the various isochrons, the concordant Rb-Sr (about 180 Myr) and U-Th-Pb (about 190 Myr) internal isochrons are interpreted as representing the time of igneous crystallization, while the Rb-Sr, Sm-Nd, and Pb-Pb whole-rock isochrons are interpreted as mixing lines, and are reasonably attributed to igneous processes such as wall-rock assimilation and magma mixing. If the approximated age of less than 200 Myr is correct, the <span class="hlt">shergottites</span> represent the youngest known extraterrestrial basalts. This conclusion supports the hypothesis that the SNC meteorites are samples of Mars.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20140011731','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20140011731"><span id="translatedtitle">Sm-Nd and Rb-Sr Isotopic Systematics of a Heavily Shocked Martian Meteorite Tissint and Petrogenesis of Depleted <span class="hlt">Shergottites</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Shih, C.-Y.; Nyquist, L. E.; Park, J.; Agee, Carl B.</p> <p>2014-01-01</p> <p>Tissint is a very fresh Martian meteorite that fell near the town of Tissint in Morocco on July 18, 2011. It contains abundant olivine megacrysts (23%) in a fine-grained matrix of pyroxene (55%), maskelynitized plagioclase (15%), opaques (4%) and melt pockets (3%) and is petrographically similar to lithologies A and C of picritic <span class="hlt">shergottite</span> EETA 79001 [1,2]. The presence of 2 types of shock-induced glasses and all 7 high-pressure mineral phases that were ever found in melt pockets of Martian meteorites suggests it underwent an intensive shock metamorphism of 25 GPa and 2000 C localized in melt pockets [2]. Mineral textures suggest that olivines, pyroxenes and plagioclases probably did not experience such hightemperature. Earlier determinations of its age yielded 596+/-23 Ma [3] and 616+/-67 Ma [4], respectively, for the Sm-Nd system and 583+/-86 Ma for the Lu-Hf system [4], in agreement with the 575+/-18 Ma age of the oldest olivine-phyric depleted <span class="hlt">shergottite</span> Dho 019 [5]. However, the exposure ages of Tissint (1 Ma [1, 6, 7]) and Dho 019 (20 Ma [8]) are very different requiring two separate ejection events. These previously determined Sm-Nd and Lu-Hf ages are older than the Ar-Ar maskelynite plateau age of 524+/-15 Ma [9], reversing the pattern usually observed for Martian meteorites. In order to clarify these age issues and place models for Tissint's petrogenesis on a firm basis, we present new Rb-Sr and Sm- Nd isotopic results for Tissint, and discuss (a) the shock effects on them and the Ar-Ar chronometer, (b) correlation of the determined ages with those of other depleted <span class="hlt">shergottites</span>, and (c) the petrogenesis of depleted <span class="hlt">shergottites</span>. Since the meteorite is a recent fall, terrestrial contamination is expected to be minimal, but, the strong shock metamorphism might be expected to compromise the equilibrium of the isotopic systems.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014AGUFMEP41B3517Z','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014AGUFMEP41B3517Z"><span id="translatedtitle">Li<span class="hlt">DAR</span> Analysis of Hector Mine Fault Scarp Degradation</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Zhang, X.; Hudnut, K. W.; Glennie, C. L.; Sousa, F.; Stock, J. M.; Akciz, S. O.</p> <p>2014-12-01</p> <p>The Mw 7.1 right-lateral strike-slip Hector Mine earthquake occurred on 10/16/1999 and generated an approximately 48 km long surface rupture. The Lavic Lake fault and the central section of the Bullion fault and several lesser faults ruptured, characterized by maximum strike slip of 5.25 ±0.85 m [Treiman, 2002]. As a very remote and un-populated area of the Mojave Desert, southern California, the study area is highly favorable for fault degradation studies with essentially no influence from vegetation or human activity. Airborne Li<span class="hlt">DAR</span> (light detection and ranging) data and terrestrial laser scanning (TLS) are used to evaluate the form and rate of degradation of scarps along the Hector Mine fault rupture, California, USA. Airborne Li<span class="hlt">DAR</span> data were acquired in 2000 and 2012 and these data were differenced using a newly developed algorithm for point cloud matching, which is improved over prior methods by accounting for scan geometry error sources. Using the bi-temporal data (scrutinizing profiles from 2000 & 2012), parameters for a fault scarp diffusion model are estimated and then a simulation result is generated to predict the evolved landform shape at the time of the 2014 TLS data set. Results are checked against TLS 2014 data collected at five key sites within the maximum slip field study area. In the past, scarp degradation has been mostly investigated using traditional survey methods (e.g., measuring elevations of points in a line perpendicular to the scarp) that require time-consuming field work and tend to introduce bias and variance due to data limitations. Airborne, mobile and terrestrial Li<span class="hlt">DAR</span> data offer great potential to precisely document and rigorously determine morphologic degradation of fault scarps [Hilley et <span class="hlt">al</span>., 2010]. In the present study, a unique set of data have been acquired at three points in time across several classic types of fault scarps and offset fault zone features. This allows progress in assessing the fitting of functions and</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014EGUGA..16.9401M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014EGUGA..16.9401M"><span id="translatedtitle">Canopy wake measurements using multiple scanning wind Li<span class="hlt">DARs</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Markfort, Corey D.; Carbajo Fuertes, Fernando; Valerio Iungo, Giacomo; Stefan, Heinz; Porté-Agel, Fernando</p> <p>2014-05-01</p> <p>Canopy wakes have been shown, in controlled wind tunnel experiments, to significantly affect the fluxes of momentum, heat and other scalars at the land and water surface over distances of ~O(1 km), see Markfort et <span class="hlt">al</span>. (EFM, 2013). However, there are currently no measurements of the velocity field downwind of a full-scale forest canopy. Point-based anemometer measurements of wake turbulence provide limited insight into the extent and details of the wake structure, whereas scanning Doppler wind Li<span class="hlt">DARs</span> can provide information on how the wake evolves in space and varies over time. For the first time, we present measurements of the velocity field in the wake of a tall patch of forest canopy. The patch consists of two uniform rows of 35-meter tall deciduous, plane trees, which border either side of the Allée de Dorigny, near the EPFL campus. The canopy is approximately 250 m long, and it is 35 m wide, along the direction of the wind. A challenge faced while making field measurements is that the wind rarely intersects a canopy normal to the edge. The resulting wake flow may be deflected relative to the mean inflow. Using multiple Li<span class="hlt">DARs</span>, we measure the evolution of the wake due to an oblique wind blowing over the canopy. One Li<span class="hlt">DAR</span> is positioned directly downwind of the canopy to measure the flow along the mean wind direction and the other is positioned near the canopy to evaluate the transversal component of the wind and how it varies with downwind distance from the canopy. Preliminary results show that the open trunk space near the base of the canopy results in a surface jet that can be detected just downwind of the canopy and farther downwind dissipates as it mixes with the wake flow above. A time-varying recirculation zone can be detected by the periodic reversal of the velocity vector near the surface, downwind of the canopy. The implications of canopy wakes for measurement and modeling of surface fluxes will be discussed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014AGUFM.A43B3268M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014AGUFM.A43B3268M"><span id="translatedtitle">Canopy wake measurements using multiple scanning wind Li<span class="hlt">DARs</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Markfort, C. D.; Carbajo Fuertes, F.; Iungo, V.; Stefan, H. G.; Porte-Agel, F.</p> <p>2014-12-01</p> <p>Canopy wakes have been shown, in controlled wind tunnel experiments, to significantly affect the fluxes of momentum, heat and other scalars at the land and water surface over distances of ˜O(1 km), see Markfort et <span class="hlt">al</span>. (EFM, 2013). However, there are currently no measurements of the velocity field downwind of a full-scale forest canopy. Point-based anemometer measurements of wake turbulence provide limited insight into the extent and details of the wake structure, whereas scanning Doppler wind Li<span class="hlt">DARs</span> can provide information on how the wake evolves in space and varies over time. For the first time, we present measurements of the velocity field in the wake of a tall patch of forest canopy. The patch consists of two uniform rows of 40-meter tall deciduous, plane trees, which border either side of the Allée de Dorigny, near the EPFL campus. The canopy is approximately 250 m long, and it is approximately 40 m wide, along the direction of the wind. A challenge faced while making field measurements is that the wind rarely intersects a canopy normal to the edge. The resulting wake flow may be deflected relative to the mean inflow. Using multiple Li<span class="hlt">DARs</span>, we measure the evolution of the wake due to an oblique wind blowing over the canopy. One Li<span class="hlt">DAR</span> is positioned directly downwind of the canopy to measure the flow along the mean wind direction and the other is positioned near the canopy to evaluate the transversal component of the wind and how it varies with downwind distance from the canopy. Preliminary results show that the open trunk space near the base of the canopy results in a surface jet that can be detected just downwind of the canopy and farther downwind dissipates as it mixes with the wake flow above. A time-varying recirculation zone can be detected by the periodic reversal of the velocity near the surface, downwind of the canopy. The implications of canopy wakes for measurement and modeling of surface fluxes will be discussed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014AGUFM.T33E..04S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014AGUFM.T33E..04S"><span id="translatedtitle">Field and Li<span class="hlt">DAR</span> observations of the Hector Mine California 1999 surface rupture</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Sousa, F.; Akciz, S. O.; Harvey, J. C.; Hudnut, K. W.; Lynch, D. K.; Scharer, K. M.; Stock, J. M.; Witkosky, R.; Kendrick, K. J.; Wespestad, C.</p> <p>2014-12-01</p> <p>We report new field- and computer-based investigations of the surface rupture of the October 16, 1999 Hector Mine Earthquake. Since May 2012, in cooperation with the United States Marine Corps Air Ground Combat Center (MCAGCC) at Twentynine Palms, CA, our team has been allowed ground and aerial access to the entire surface rupture. We have focused our new field-based research and imagery analysis along the ~10 kilometer-long maximum slip zone (MSZ) which roughly corresponds to the zone of >4 meter dextral horizontal offset. New data include: 1) a 1 km wide aerial Li<span class="hlt">DAR</span> survey along the entire surface rupture (@ 10 shots/m2, May 2012, www.opentopography.org); 2) terrestrial Li<span class="hlt">DAR</span> surveys at 5 sites within the MSZ (@ >1000 shots/m2, April 2014); 3) low altitude aerial photography and ground based photography of the entire MSZ; 4) a ground-truthed database of 87 out of the 94 imagery-based offset measurements made within the MSZ; and 5) a database of 50 new field-based offset measurements made within the MSZ by our team on the ground, 31 of which have also been made on the computer (Ladicaoz) with both the 2000 Li<span class="hlt">DAR</span> data (@ 0.5 m DEM resolution; Chen et <span class="hlt">al</span>, in review) and 2012 Li<span class="hlt">DAR</span> data (@ 35 cm DEM resolution; our team). New results to date include 1) significant variability (> 2 m) in horizontal offsets measured along short distances of the surface rupture (~100 m) within segments of the surface rupture that are localized to a single fault strand; 2) strong dependence of decadal scale fault scarp preservation on local lithology (bedrock vs. alluvial fan vs. fine sediment) and geomorphology (uphill vs. downhill facing scarp); 3) newly observed offset features which were never measured during the post-event field response; 4) newly observed offset features too small to be resolved in airborne Li<span class="hlt">DAR</span> data (< 1 m); 5) nearly 25% of Li<span class="hlt">DAR</span> imagery-based measurements that were later ground-truthed were judged by our team to warrant removal from the database due to</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015GeCoA.166..234H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015GeCoA.166..234H"><span id="translatedtitle">Evidence for the exsolution of Cl-rich fluids in martian magmas: Apatite petrogenesis in the enriched lherzolitic <span class="hlt">shergottite</span> Northwest Africa 7755</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Howarth, G. H.; Pernet-Fisher, J. F.; Bodnar, R. J.; Taylor, L. A.</p> <p>2015-10-01</p> <p>Martian meteorite Northwest Africa 7755 is a new example of an enriched, lherzolitic <span class="hlt">shergottite</span>, containing some of the coarsest-grained apatite yet identified in <span class="hlt">shergottite</span> meteorites. Their size has permitted detailed observations of volatile distributions within single grains. We have demonstrated that some apatites have been invaded by shock melts, which act to devolatilize parts of grains, resulting in significant Cl-enrichment in the adjacent regions. The extent of chemical heterogeneity within single grains must be carefully considered in other <span class="hlt">shergottites</span>, so that the effects of secondary modification of apatites are well-constrained, prior to interpreting the volatile contents and primary magmatic processes. Apatite grains unaffected by shock melts are OH-F enriched and Cl-poor (∼F50Cl14OH36), relative to interstitial apatites reported in other <span class="hlt">shergottites</span>. The volatile compositions are similar to interstitial apatites reported in terrestrial mafic intrusions. Such apatites in terrestrial intrusions are argued to have formed after significant Cl-loss due to the exsolution and migration of Cl-rich brines. Calculated relative F2, Cl2, and H2O fugacities for NWA 7755 apatites show a trend of degassing rather than fractionation, noted in previous studies. Indeed, we interpret the volatile contents of apatites analyzed in the cumulate <span class="hlt">shergottite</span> NWA 7755 to represent snapshots of the evolving late-stage residual liquid during exsolution of a Cl-rich brine. This fluid phase has subsequently been lost from an open magma system, migrating upward through the cumulate sequence enriching residual liquids in Cl. Alternatively, it formed a hydrothermal system in the martian crust surrounding the intrusion. Furthermore, by comparison with terrestrial examples, we suggest that the late-stage evolution of volatile-bearing phases in NWA 7755 is similar to that of comparable terrestrial mafic rocks. Primary cumulus apatites are F-rich, whereas interstitial apatites</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2015AGUFM.C42B..05G&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2015AGUFM.C42B..05G&link_type=ABSTRACT"><span id="translatedtitle">Calculating Li<span class="hlt">DAR</span> Point Cloud Uncertainty and Propagating Uncertainty to Snow-Water Equivalent Data Products</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Gadomski, P. J.; Deems, J. S.; Glennie, C. L.; Hartzell, P. J.; Butler, H.; Finnegan, D. C.</p> <p>2015-12-01</p> <p>The use of high-resolution topographic data in the form of three-dimensional point clouds obtained from laser scanning systems (Li<span class="hlt">DAR</span>) is becoming common across scientific disciplines.However little consideration has typically been given to the accuracy and the precision of Li<span class="hlt">DAR</span>-derived measurements at the individual point scale.Numerous disparate sources contribute to the aggregate precision of each point measurement, including uncertainties in the range measurement, measurement of the attitude and position of the Li<span class="hlt">DAR</span> collection platform, uncertainties associated with the interaction between the laser pulse and the target surface, and more.We have implemented open-source software tools to calculate per-point stochastic measurement errors for a point cloud using the general Li<span class="hlt">DAR</span> georeferencing equation.We demonstrate the use of these propagated uncertainties by applying our methods to data collected by the Airborne Snow Observatory <span class="hlt">ALS</span>, a NASA JPL project using a combination of airborne hyperspectral and Li<span class="hlt">DAR</span> data to estimate snow-water equivalent distributions over full river basins.We present basin-scale snow depth maps with associated uncertainties, and demonstrate the propagation of those uncertainties to snow volume and snow-water equivalent calculations.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2016EGUGA..1816266K&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2016EGUGA..1816266K&link_type=ABSTRACT"><span id="translatedtitle">Approach to voxel-based carbon stock quanticiation using Li<span class="hlt">DAR</span> data in tropical rainforest, Brunei</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kim, Eunji; Piao, Dongfan; Lee, Jongyeol; Lee, Woo-Kyun; Yoon, Mihae; Moon, Jooyeon</p> <p>2016-04-01</p> <p>Forest is an important means to adapt climate change as the only carbon sink recognized by the international community (KFS 2009). According to the Intergovernmental Panel on Climate Change (IPCC) 5th Assessment Report (AR5), Agriculture, Forestry, and Other Land Use (AFOLU) sectors including forestry contributed 24% of total anthropogenic emissions in 2010 (IPCC 2014; Tubiello et <span class="hlt">al</span>. 2015). While all sectors excluding AFOLU have increased Greenhouse Gas (GHG) emissions, land use sectors including forestry remains similar level as before due to decreasing deforestation and increasing reforestation. In earlier researches, optical imagery has been applied for analysis (Jakubowski et <span class="hlt">al</span>. 2013). Optical imagery collects spectral information in 2D. It is difficult to effectively quantify forest stocks, especially in dense forest (Cui et <span class="hlt">al</span>. 2012). To detect individual trees information from remotely sensed data, Light detection and ranging (Li<span class="hlt">DAR</span>) has been used (Hyyppäet <span class="hlt">al</span>. 2001; Persson et <span class="hlt">al</span>. 2002; Chen et <span class="hlt">al</span>. 2006). Moreover, Li<span class="hlt">DAR</span> has the ability to actively acquire vertical tree information such as tree height using geo-registered 3D points (Kwak et <span class="hlt">al</span>. 2007). In general, however, geo-register 3D point was used with a raster format which contains only 2D information by missing all the 3D data. Therefore, this research aimed to use the volumetric pixel (referred as "voxel") approach using Li<span class="hlt">DAR</span> data in tropical rainforest, Brunei. By comparing the parameters derived from voxel based Li<span class="hlt">DAR</span> data and field measured data, we examined the relationships between them for the quantification of forest carbon. This study expects to be more helpful to take advantage of the strategic application of climate change adaption.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015Geomo.246..531A','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015Geomo.246..531A"><span id="translatedtitle">Using Li<span class="hlt">DAR</span> to characterize logjams in lowland rivers</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Abalharth, Mahdi; Hassan, Marwan A.; Klinkenberg, Brian; Leung, Vivian; McCleary, Richard</p> <p>2015-10-01</p> <p>Logjams significantly influence watershed hydrology, flow regime, channel morphology and stability, and processes in lowland rivers. Consequently, logjams play a major role in the existence and conservation of the riparian and aquatic ecosystems along major waterways. In this paper, we attempt to detect and quantify logjams in river channels using Li<span class="hlt">DAR</span> technology in conjunction with traditional fieldwork. To the best of our knowledge, Li<span class="hlt">DAR</span>-based analysis has not been used to characterize logjams in streams. Overall, when applied in a lowland river environment, Li<span class="hlt">DAR</span>-based analysis demonstrates a comprehensive solution for detecting logjams in relation to the fieldwork, with a low rate of omission. A filtered approach predicted the presence of 95% of fieldwork-reported logjams (a 5% rate of omission), but also identified six logjams not identified in the field (a 10% rate of commission). A nonfiltered approach identified 87% of field-reported logjams, producing a 13% rate of omission and a 6.7% rate of commission. Dimension measurements were more consistent in the filtered Li<span class="hlt">DAR</span> approach, showing 53%, 34%, and 90% of R2 improvements for the length, width, and height, respectively, over the unfiltered Li<span class="hlt">DAR</span> values. As vegetation cover hindered accurate delineation of logjam boundaries by Li<span class="hlt">DAR</span>, field and Li<span class="hlt">DAR</span> measurements of nonvegetation-obstructed logjams were more highly correlated than the field and Li<span class="hlt">DAR</span> measurements of partially and completely vegetation-obstructed logjams.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://eric.ed.gov/?q=Roosevelt+AND+Eleanor&pg=2&id=EJ307621','ERIC'); return false;" href="http://eric.ed.gov/?q=Roosevelt+AND+Eleanor&pg=2&id=EJ307621"><span id="translatedtitle">Eleanor Roosevelt Resigns from the <span class="hlt">DAR</span>: A Study in Conscience.</span></a></p> <p><a target="_blank" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>Freeman, Elsie T.; And Others</p> <p>1984-01-01</p> <p>Because the Daughters of the American Revolution's (<span class="hlt">DAR</span>) Black exclusion rule prevented Black singer Marion Anderson from performing in the <span class="hlt">DAR</span> auditorium in 1939, Eleanor Roosevelt resigned from the organization. Primary source materials regarding this incident and learning activities for secondary level students are presented. (RM)</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2008AGUFM.P53A1432W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2008AGUFM.P53A1432W"><span id="translatedtitle">Unique Ground-Truthing of a <span class="hlt">Shergottitic</span> Lithology as a Potential Orbital End-Member Provided by Mini-TES/MER and Laboratory TIR Data of Terrestrial Shocked Basalt</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Wright, S.; Christensen, P.; Wyatt, M.</p> <p>2008-12-01</p> <p>The majority of the equatorial regions of Mars are basaltic sands labeled Surface Type 1 (ST1). This MGS TES orbital thermal infrared (TIR) end-member is often compared to laboratory TIR data of Deccan Trap flood basalt from central India. Although subtle spectral differences exist (to be shown), the two likely have similar abundances and composition of labradorite and clinopyroxenes augite and pigeonite. This has been confirmed by recent works utilizing Mini-TES data of Meridiani sands and Gusev soils (both ST1) along with data from other MER instruments. Further, the TIR spectrum of Deccan basalt from Lonar Crater, India that was shocked 20-40 GPa is an exact match to the TIR spectrum of the Los Angeles <span class="hlt">shergottite</span> in that both contain 45% maskelynite and 35% augite/pigeonite. This strengthens the comparison of ST1 to Deccan basalt and suggests that Los Angeles was ST1 bedrock before ejection. However, the TIR spectrum of ST1 and Deccan basalt both differ from the laboratory spectra of most basaltic <span class="hlt">shergottites</span>, which contain more clinopyroxene than plagioclase. Further, the <span class="hlt">shergottites</span> contain shattered clinopyroxenes and maskelynite, or plagioclase feldspar shock compressed to a diaplectic glass of plagioclase composition, that was created in the impact event that launched them from Mars. Presumably, the original basaltic bedrock from which <span class="hlt">shergottites</span> originated contain the original plagioclase feldspar and unshattered clinopyroxenes. Whereas there exists evidence for olivine and orthopyroxene on Mars, large occurrences of these CPX-rich <span class="hlt">shergottites</span> (not to be confused with pyroxenites or Nakhlites) have not been located using a laboratory TIR spectrum as an orbital end-member. However, one particular MER-B target named Bounce Rock has APXS and Mössbauer spectra similar to some <span class="hlt">shergottites</span> such as Zagami. Mineral abundances resulting from the deconvolution of the Mini-TES spectrum of Bounce Rock, where the effects of dust have been removed, are similar</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20080013380','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20080013380"><span id="translatedtitle">Sulfur and Iron Speciation in Gas-rich Impact-melt Glasses from Basaltic <span class="hlt">Shergottites</span> Determined by Microxanes</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Sutton, S. R.; Rao, M. N.; Nyquist, L. E.</p> <p>2008-01-01</p> <p>Sulfur is abundantly present as sulfate near Martian surface based on chemical and mineralogical investigations on soils and rocks in Viking, Pathfinder and MER missions. Jarosite is identified by Mossbauer studies on rocks at Meridian and Gusev, whereas MgSO4 is deduced from MgO - SO3 correlations in Pathfinder MER and Viking soils. Other sulfate minerals such as gypsum and alunogen/ S-rich aluminosilicates and halides are detected only in martian meteorites such as <span class="hlt">shergottites</span> and nakhlites using SEM/FE-SEM and EMPA techniques. Because sulfur has the capacity to occur in multiple valence states, determination of sulfur speciation (sulfide/ sulfate) in secondary mineral assemblages in soils and rocks near Mars surface may help us understand whether the fluid-rock interactions occurred under oxidizing or reducing conditions. To understand the implications of these observations for the formation of the Gas-rich Impact-melt (GRIM) glasses, we determined the oxidation state of Fe in the GRIM glasses using Fe K micro-XANES techniques.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013AGUFMIN21A1387C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013AGUFMIN21A1387C"><span id="translatedtitle">Classification and Characterization of Neotropical Rainforest Vegetation from Hyperspectral and Li<span class="hlt">DAR</span> Data</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Crawford, M. M.; Prasad, S.; Jung, J.; Yang, H.; Zhang, Y.</p> <p>2013-12-01</p> <p>Mapping species and forest vertical structure at regional, continental, and global scale is of increasing importance for climate science and decision support systems. Remote sensing technologies have been widely utilized to achieve this goal since they help overcome limitations of the direct and indirect measurement approaches. While the use of multi-sensor data for characterizing forest structure has gained significant attention in recent years, research on the integration of full waveform Li<span class="hlt">DAR</span> and hyperspectral data for a) classification and b) characterization of vegetation structure has been limited. Given sufficient labeled ground reference samples, supervised learning methods have evolved to effectively classify data in a high dimensional feature space. However, it is expensive and time-consuming to obtain labeled data, although the very high dimensionality of feature spaces from hyperspectral and Li<span class="hlt">DAR</span> inputs make it difficult to design reliable classifiers with a limited quantity of labeled data. Therefore, it is important to concentrate on developing training data sets which are the most 'informative' and 'useful' for the classification task. Active learning (<span class="hlt">AL</span>) was developed in the machine learning community, and has been demonstrated to be useful for classification of remote sensing data. In the active learning framework, classifiers are initially trained on a very limited pool of training samples, but additional informative and representative samples are identified from the abundant unlabeled data, labeled, and then inducted into this pool, thereby growing the training dataset in a systematic way. The goal is to choose data points such that a more accurate classification boundary is learned. We propose a novel Multi-kernel Active Learning (MKL-<span class="hlt">AL</span>) approach that incorporates features from multiple sensors with an automatically optimized kernel composite ¬function, and kernel parameters are selected intelligently during the <span class="hlt">AL</span> learning process. The</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014AGUFM.V13C4800W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014AGUFM.V13C4800W"><span id="translatedtitle">Lava flow texture Li<span class="hlt">DAR</span> signatures</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Whelley, P.; Garry, W. B.; Scheidt, S. P.; Irwin, R. P., III; Fox, J.; Bleacher, J. E.; Hamilton, C. W.</p> <p>2014-12-01</p> <p>High-resolution point clouds and digital elevation models (DEMs) are used to investigate lava textures on the Big Island of Hawaii. An experienced geologist can distinguish fresh or degraded lava textures (e.g., blocky, a'a and pahoehoe) visually in the field. Lava texture depends significantly on eruption conditions, and it is therefore instructive, if accurately determined. In places where field investigations are prohibitive (e.g., Mercury, Venus, the Moon, Mars, Io and remote regions on Earth) lava texture must be assessed from remote sensing data. A reliable method for differentiating lava textures in remote sensing data remains elusive. We present preliminary results comparing properties of lava textures observed in airborne and terrestrial Light Detection and Ranging (Li<span class="hlt">DAR</span>) data. Airborne data, in this study, were collected in 2011 by Airborne 1 Corporation and have a ~1m point spacing. The authors collected the terrestrial data during a May 2014 field season. The terrestrial scans have a heterogeneous point density. Points close to the scanner are 1 mm apart while 200 m in the distance points are 10 cm apart. Both platforms offer advantages and disadvantages beyond the differences in scale. Terrestrial scans are a quantitative representation of what a geologist sees "on the ground". Airborne scans are a point of view routinely imaged by other remote sensing tools, and can therefore be quickly compared to complimentary data sets (e.g., spectral scans or image data). Preliminary results indicate that Li<span class="hlt">DAR</span>-derived surface roughness, from both platforms, is useful for differentiating lava textures, but at different spatial scales. As all lava types are quite rough, it is not simply roughness that is the most advantageous parameter; rather patterns in surface roughness can be used to differentiate lava surfaces of varied textures. This work will lead to faster and more reliable volcanic mapping efforts for planetary exploration as well as terrestrial</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013AGUFM.B23B0557R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013AGUFM.B23B0557R"><span id="translatedtitle">Using Li<span class="hlt">DAR</span> to Estimate Total Aboveground Biomass of Redwood Stands in the Jackson Demonstration State Forest, Mendocino, California</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Rao, M.; Vuong, H.</p> <p>2013-12-01</p> <p>The overall objective of this study is to develop a method for estimating total aboveground biomass of redwood stands in Jackson Demonstration State Forest, Mendocino, California using airborne Li<span class="hlt">DAR</span> data. Li<span class="hlt">DAR</span> data owing to its vertical and horizontal accuracy are increasingly being used to characterize landscape features including ground surface elevation and canopy height. These Li<span class="hlt">DAR</span>-derived metrics involving structural signatures at higher precision and accuracy can help better understand ecological processes at various spatial scales. Our study is focused on two major species of the forest: redwood (Sequoia semperirens [D.Don] Engl.) and Douglas-fir (Pseudotsuga mensiezii [Mirb.] Franco). Specifically, the objectives included linear regression models fitting tree diameter at breast height (dbh) to Li<span class="hlt">DAR</span> derived height for each species. From 23 random points on the study area, field measurement (dbh and tree coordinate) were collected for more than 500 trees of Redwood and Douglas-fir over 0.2 ha- plots. The USFS-FUSION application software along with its Li<span class="hlt">DAR</span> Data Viewer (LDV) were used to to extract Canopy Height Model (CHM) from which tree heights would be derived. Based on the Li<span class="hlt">DAR</span> derived height and ground based dbh, a linear regression model was developed to predict dbh. The predicted dbh was used to estimate the biomass at the single tree level using Jenkin's formula (Jenkin et <span class="hlt">al</span> 2003). The linear regression models were able to explain 65% of the variability associated with Redwood's dbh and 80% of that associated with Douglas-fir's dbh.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20080048128','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20080048128"><span id="translatedtitle">Processing Li<span class="hlt">DAR</span> Data to Predict Natural Hazards</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Fairweather, Ian; Crabtree, Robert; Hager, Stacey</p> <p>2008-01-01</p> <p>ELF-Base and ELF-Hazards (wherein 'ELF' signifies 'Extract Li<span class="hlt">DAR</span> Features' and 'Li<span class="hlt">DAR</span>' signifies 'light detection and ranging') are developmental software modules for processing remote-sensing Li<span class="hlt">DAR</span> data to identify past natural hazards (principally, landslides) and predict future ones. ELF-Base processes raw Li<span class="hlt">DAR</span> data, including Li<span class="hlt">DAR</span> intensity data that are often ignored in other software, to create digital terrain models (DTMs) and digital feature models (DFMs) with sub-meter accuracy. ELF-Hazards fuses raw Li<span class="hlt">DAR</span> data, data from multispectral and hyperspectral optical images, and DTMs and DFMs generated by ELF-Base to generate hazard risk maps. Advanced algorithms in these software modules include line-enhancement and edge-detection algorithms, surface-characterization algorithms, and algorithms that implement innovative data-fusion techniques. The line-extraction and edge-detection algorithms enable users to locate such features as faults and landslide headwall scarps. Also implemented in this software are improved methodologies for identification and mapping of past landslide events by use of (1) accurate, ELF-derived surface characterizations and (2) three Li<span class="hlt">DAR</span>/optical-data-fusion techniques: post-classification data fusion, maximum-likelihood estimation modeling, and hierarchical within-class discrimination. This software is expected to enable faster, more accurate forecasting of natural hazards than has previously been possible.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2015AGUFM.B43C0565Z&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2015AGUFM.B43C0565Z&link_type=ABSTRACT"><span id="translatedtitle">Exploring tree species signature using waveform Li<span class="hlt">DAR</span> data</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Zhou, T.; Popescu, S. C.; Krause, K.</p> <p>2015-12-01</p> <p>Successful classification of tree species with waveform Li<span class="hlt">DAR</span> data would be of considerable value to estimate the biomass stocks and changes in forests. Current approaches emphasize converting the full waveform data into discrete points to get larger amount of parameters and identify tree species using several discrete-points variables. However, ignores intensity values and waveform shapes which convey important structural characteristics. The overall goal of this study was to employ the intensity and waveform shape of individual tree as the waveform signature to detect tree species. The data was acquired by the National Ecological Observatory Network (NEON) within 250*250 m study area located in San Joaquin Experimental Range. Specific objectives were to: (1) segment individual trees using the smoothed canopy height model (CHM) derived from discrete Li<span class="hlt">DAR</span> points; (2) link waveform Li<span class="hlt">DAR</span> with above individual tree boundaries to derive sample signatures of three tree species and use these signatures to discriminate tree species in a large area; and (3) compare tree species detection results from discrete Li<span class="hlt">DAR</span> data and waveform Li<span class="hlt">DAR</span> data. An overall accuracy of the segmented individual tree of more than 80% was obtained. The preliminary results show that compared with the discrete Li<span class="hlt">DAR</span> data, the waveform Li<span class="hlt">DAR</span> signature has a higher potential for accurate tree species classification.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2016ISPAr49B3..283L&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2016ISPAr49B3..283L&link_type=ABSTRACT"><span id="translatedtitle">Tensor Modeling Based for Airborne Li<span class="hlt">DAR</span> Data Classification</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Li, N.; Liu, C.; Pfeifer, N.; Yin, J. F.; Liao, Z. Y.; Zhou, Y.</p> <p>2016-06-01</p> <p>Feature selection and description is a key factor in classification of Earth observation data. In this paper a classification method based on tensor decomposition is proposed. First, multiple features are extracted from raw Li<span class="hlt">DAR</span> point cloud, and raster Li<span class="hlt">DAR</span> images are derived by accumulating features or the "raw" data attributes. Then, the feature rasters of Li<span class="hlt">DAR</span> data are stored as a tensor, and tensor decomposition is used to select component features. This tensor representation could keep the initial spatial structure and insure the consideration of the neighborhood. Based on a small number of component features a k nearest neighborhood classification is applied.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_5");'>5</a></li> <li><a href="#" onclick='return showDiv("page_6");'>6</a></li> <li class="active"><span>7</span></li> <li><a href="#" onclick='return showDiv("page_8");'>8</a></li> <li><a href="#" onclick='return showDiv("page_9");'>9</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_7 --> <div id="page_8" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_6");'>6</a></li> <li><a href="#" onclick='return showDiv("page_7");'>7</a></li> <li class="active"><span>8</span></li> <li><a href="#" onclick='return showDiv("page_9");'>9</a></li> <li><a href="#" onclick='return showDiv("page_10");'>10</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="141"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20160003470','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20160003470"><span id="translatedtitle">The Mineralogy, Geochemistry, and Redox State of Multivalent Cations During the Crystallization of Primitive <span class="hlt">Shergottitic</span> Liquids at Various (f)O2. Insights into the (f)O2 Fugacity of the Martian Mantle and Crustal Influences on Redox Conditions of Martian Magmas.</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Shearer, C. K.; Bell, A. S.; Burger, P. V.; Papike, J. J.; Jones, J.; Le, L.; Muttik, N.</p> <p>2016-01-01</p> <p>The (f)O2 [oxygen fugacity] of crystallization for martian basalts has been estimated in various studies to range from IW-1 to QFM+4 [1-3]. A striking geochemical feature of the <span class="hlt">shergottites</span> is the large range in initial Sr isotopic ratios and initial epsilon(sup Nd) values. Studies by observed that within the <span class="hlt">shergottite</span> group the (f)O2 [oxygen fugacity] of crystallization is highly correlated with these chemical and isotopic characteristics with depleted <span class="hlt">shergottites</span> generally crystallizing at reduced conditions and enriched <span class="hlt">shergottites</span> crystallizing under more oxidizing conditions. More recent work has shown that (f)O2 [oxygen fugacity] changed during the crystallization of these magmas from one order of magnitude in Y980459 (Y98) to several orders of magnitude in Larkman Nunatak 06319. These real or apparent variations within single <span class="hlt">shergottitic</span> magmas have been attributed to mixing of a xenocrystic olivine component, volatile loss-water disassociation, auto-oxidation during crystallization of mafic phases, and assimilation of an oxidizing crustal component (e.g. sulfate). In contrast to the <span class="hlt">shergottites</span>, augite basalts such as NWA 8159 are highly depleted yet appear to be highly oxidized (e.g. QFM+4). As a first step in attempting to unravel petrologic complexities that influence (f)O2 [oxygen fugacity] in martian magmas, this study explores the effect of (f)O2 [oxygen fugacity] on the liquid line of descent (LLD) for a primitive <span class="hlt">shergottite</span> liquid composition (Y98). The results of this study will provide a fundamental basis for reconstructing the record of (f)O2 [oxygen fugacity] in <span class="hlt">shergottites</span> and other martian basalts, its effect on both mineral chemistries and valence state partitioning, and a means for examining the role of crystallization (and other more complex processes) on the petrologic linkages between olivine-phyric and pyroxene-plagioclase <span class="hlt">shergottites</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20160003501','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20160003501"><span id="translatedtitle">Constraints on Mantle Plume Melting Conditions in the Martian Mantle Based on Improved Melting Phase Relationships of Olivine-Phyric <span class="hlt">Shergottite</span> Yamato 980459</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Kiefer, Walter S.; Rapp, Jennifer F.; Usui, Tomohiro; Draper, David S.; Filiberto, Justin</p> <p>2016-01-01</p> <p>Martian meteorite Yamato 980459 (hereafter Y98) is an olivine-phyric <span class="hlt">shergottite</span> that has been interpreted as closely approximating a martian mantle melt [1-4], making it an important constraint on adiabatic decompression melting models. It has long been recognized that low pressure melting of the Y98 composition occurs at extremely high temperatures relative to martian basalts (1430 degC at 1 bar), which caused great difficulties in a previous attempt to explain Y98 magma generation via a mantle plume model [2]. However, previous studies of the phase diagram were limited to pressures of 2 GPa and less [2, 5], whereas decompression melting in the present-day martian mantle occurs at pressures of 3-7 GPa, with the shallow boundary of the melt production zone occurring just below the base of the thermal lithosphere [6]. Recent experimental work has now extended our knowledge of the Y98 melting phase relationships to 8 GPa. In light of this improved petrological knowledge, we are therefore reassessing the constraints that Y98 imposes on melting conditions in martian mantle plumes. Two recently discovered olivine- phyric <span class="hlt">shergottites</span>, Northwest Africa (NWA) 5789 and NWA 6234, may also be primary melts from the martian mantle [7, 8]. However, these latter meteorites have not been the subject of detailed experimental petrology studies, so we focus here on Y98.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2016EGUGA..18.5416K&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2016EGUGA..18.5416K&link_type=ABSTRACT"><span id="translatedtitle">Shipborne Li<span class="hlt">DAR</span> system for coastal change monitoring</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kim, chang hwan; Park, chang hong; Kim, hyun wook; hyuck Kim, won; Lee, myoung hoon; Park, hyeon yeong</p> <p>2016-04-01</p> <p>Coastal areas, used as human utilization areas like leisure space, medical care, ports and power plants, etc., are regions that are continuously changing and interconnected with oceans and land and the sea level has risen by about 8cm (1.9mm / yr) due to global warming from 1964 year to 2006 year in Korea. Coastal erosion due to sea-level rise has caused the problem of marine ecosystems and loss of tourism resources, etc. Regular monitoring of coastal erosion is essential at key locations with such volatility. But the survey method of land mobile Li<span class="hlt">DAR</span> (light detection and ranging) system has much time consuming and many restrictions. For effective monitoring beach erosion, KIOST (Korea Institute of Ocean Science & Technology) has constructed a shipborne mobile Li<span class="hlt">DAR</span> system. The shipborne mobile Li<span class="hlt">DAR</span> system comprised a land mobile Li<span class="hlt">DAR</span> (RIEGL LMS-420i), an INS (inertial navigation system, MAGUS Inertial+), a RTKGPS (LEICA GS15 GS25), and a fixed platform. The shipborne mobile Li<span class="hlt">DAR</span> system is much more effective than a land mobile Li<span class="hlt">DAR</span> system in the measuring of fore shore areas without shadow zone. Because the vessel with the shipborne mobile Li<span class="hlt">DAR</span> system is continuously moved along the shoreline, it is possible to efficiently survey a large area in a relatively short time. Effective monitoring of the changes using the constructed shipborne mobile Li<span class="hlt">DAR</span> system for seriously eroded coastal areas will be able to contribute to coastal erosion management and response.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://dx.doi.org/10.1002/hyp.9225','USGSPUBS'); return false;" href="http://dx.doi.org/10.1002/hyp.9225"><span id="translatedtitle">Modelling rating curves using remotely sensed Li<span class="hlt">DAR</span> data</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Nathanson, Marcus; Kean, Jason W.; Grabs, Thomas J.; Seibert, Jan; Laudon, Hjalmar; Lyon, Steve W.</p> <p>2012-01-01</p> <p>Accurate stream discharge measurements are important for many hydrological studies. In remote locations, however, it is often difficult to obtain stream flow information because of the difficulty in making the discharge measurements necessary to define stage-discharge relationships (rating curves). This study investigates the feasibility of defining rating curves by using a fluid mechanics-based model constrained with topographic data from an airborne Li<span class="hlt">DAR</span> scanning. The study was carried out for an 8m-wide channel in the boreal landscape of northern Sweden. Li<span class="hlt">DAR</span> data were used to define channel geometry above a low flow water surface along the 90-m surveyed reach. The channel topography below the water surface was estimated using the simple assumption of a flat streambed. The roughness for the modelled reach was back calculated from a single measurment of discharge. The topographic and roughness information was then used to model a rating curve. To isolate the potential influence of the flat bed assumption, a 'hybrid model' rating curve was developed on the basis of data combined from the Li<span class="hlt">DAR</span> scan and a detailed ground survey. Whereas this hybrid model rating curve was in agreement with the direct measurements of discharge, the Li<span class="hlt">DAR</span> model rating curve was equally in agreement with the medium and high flow measurements based on confidence intervals calculated from the direct measurements. The discrepancy between the Li<span class="hlt">DAR</span> model rating curve and the low flow measurements was likely due to reduced roughness associated with unresolved submerged bed topography. Scanning during periods of low flow can help minimize this deficiency. These results suggest that combined ground surveys and Li<span class="hlt">DAR</span> scans or multifrequency Li<span class="hlt">DAR</span> scans that see 'below' the water surface (bathymetric Li<span class="hlt">DAR</span>) could be useful in generating data needed to run such a fluid mechanics-based model. This opens a realm of possibility to remotely sense and monitor stream flows in channels in remote</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3231455','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3231455"><span id="translatedtitle">Georeferenced Li<span class="hlt">DAR</span> 3D Vine Plantation Map Generation</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Llorens, Jordi; Gil, Emilio; Llop, Jordi; Queraltó, Meritxell</p> <p>2011-01-01</p> <p>The use of electronic devices for canopy characterization has recently been widely discussed. Among such devices, Li<span class="hlt">DAR</span> sensors appear to be the most accurate and precise. Information obtained with Li<span class="hlt">DAR</span> sensors during reading while driving a tractor along a crop row can be managed and transformed into canopy density maps by evaluating the frequency of Li<span class="hlt">DAR</span> returns. This paper describes a proposed methodology to obtain a georeferenced canopy map by combining the information obtained with Li<span class="hlt">DAR</span> with that generated using a GPS receiver installed on top of a tractor. Data regarding the velocity of Li<span class="hlt">DAR</span> measurements and UTM coordinates of each measured point on the canopy were obtained by applying the proposed transformation process. The process allows overlap of the canopy density map generated with the image of the intended measured area using Google Earth®, providing accurate information about the canopy distribution and/or location of damage along the rows. This methodology was applied and tested on different vine varieties and crop stages in two important vine production areas in Spain. The results indicate that the georeferenced information obtained with Li<span class="hlt">DAR</span> sensors appears to be an interesting tool with the potential to improve crop management processes. PMID:22163952</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/22163952','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/22163952"><span id="translatedtitle">Georeferenced Li<span class="hlt">DAR</span> 3D vine plantation map generation.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Llorens, Jordi; Gil, Emilio; Llop, Jordi; Queraltó, Meritxell</p> <p>2011-01-01</p> <p>The use of electronic devices for canopy characterization has recently been widely discussed. Among such devices, Li<span class="hlt">DAR</span> sensors appear to be the most accurate and precise. Information obtained with Li<span class="hlt">DAR</span> sensors during reading while driving a tractor along a crop row can be managed and transformed into canopy density maps by evaluating the frequency of Li<span class="hlt">DAR</span> returns. This paper describes a proposed methodology to obtain a georeferenced canopy map by combining the information obtained with Li<span class="hlt">DAR</span> with that generated using a GPS receiver installed on top of a tractor. Data regarding the velocity of Li<span class="hlt">DAR</span> measurements and UTM coordinates of each measured point on the canopy were obtained by applying the proposed transformation process. The process allows overlap of the canopy density map generated with the image of the intended measured area using Google Earth(®), providing accurate information about the canopy distribution and/or location of damage along the rows. This methodology was applied and tested on different vine varieties and crop stages in two important vine production areas in Spain. The results indicate that the georeferenced information obtained with Li<span class="hlt">DAR</span> sensors appears to be an interesting tool with the potential to improve crop management processes. PMID:22163952</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015JPRS..104..144F','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015JPRS..104..144F"><span id="translatedtitle">Validation of Canopy Height Profile methodology for small-footprint full-waveform airborne Li<span class="hlt">DAR</span> data in a discontinuous canopy environment</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Fieber, Karolina D.; Davenport, Ian J.; Tanase, Mihai A.; Ferryman, James M.; Gurney, Robert J.; Becerra, Victor M.; Walker, Jeffrey P.; Hacker, Jorg M.</p> <p>2015-06-01</p> <p>A Canopy Height Profile (CHP) procedure presented in Harding et <span class="hlt">al</span>. (2001) for large footprint Li<span class="hlt">DAR</span> data was tested in a closed canopy environment as a way of extracting vertical foliage profiles from Li<span class="hlt">DAR</span> raw-waveform. In this study, an adaptation of this method to small-footprint data has been shown, tested and validated in an Australian sparse canopy forest at plot- and site-level. Further, the methodology itself has been enhanced by implementing a dataset-adjusted reflectance ratio calculation according to Armston et <span class="hlt">al</span>. (2013) in the processing chain, and tested against a fixed ratio of 0.5 estimated for the laser wavelength of 1550 nm. As a by-product of the methodology, effective leaf area index (LAIe) estimates were derived and compared to hemispherical photography values. To assess the influence of Li<span class="hlt">DAR</span> aggregation area size on the estimates in a sparse canopy environment, Li<span class="hlt">DAR</span> CHPs and LAIes were generated by aggregating waveforms to plot- and site-level footprints (plot/site-aggregated) as well as in 5 m grids (grid-processed). Li<span class="hlt">DAR</span> profiles were then compared to field biomass profiles generated based on field tree measurements. The correlation between field and Li<span class="hlt">DAR</span> profiles was very high, with a mean R2 of 0.75 at plot-level and 0.86 at site-level for 55 plots and the corresponding 11 sites. Gridding had almost no impact on the correlation between Li<span class="hlt">DAR</span> and field profiles (only marginally improvement), nor did the dataset-adjusted reflectance ratio. However, gridding and the dataset-adjusted reflectance ratio were found to improve the correlation between raw-waveform Li<span class="hlt">DAR</span> and hemispherical photography LAIe estimates, yielding the highest correlations of 0.61 at plot-level and of 0.83 at site-level. This proved the validity of the approach and superiority of dataset-adjusted reflectance ratio of Armston et <span class="hlt">al</span>. (2013) over a fixed ratio of 0.5 for LAIe estimation, as well as showed the adequacy of small-footprint Li<span class="hlt">DAR</span> data for LAIe estimation in</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2016M%26PS...51..407W&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2016M%26PS...51..407W&link_type=ABSTRACT"><span id="translatedtitle">Noble gases in 18 Martian meteorites and angrite Northwest Africa 7812—Exposure ages, trapped gases, and a re-evaluation of the evidence for solar cosmic ray-produced neon in <span class="hlt">shergottites</span> and other achondrites</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Wieler, R.; Huber, L.; Busemann, H.; Seiler, S.; Leya, I.; Maden, C.; Masarik, J.; Meier, M. M. M.; Nagao, K.; Trappitsch, R.; Irving, A. J.</p> <p>2016-02-01</p> <p>We present noble gas data for 16 <span class="hlt">shergottites</span>, 2 nakhlites (NWA 5790, NWA 10153), and 1 angrite (NWA 7812). Noble gas exposure ages of the <span class="hlt">shergottites</span> fall in the 1-6 Ma range found in previous studies. Three depleted olivine-phyric <span class="hlt">shergottites</span> (Tissint, NWA 6162, NWA 7635) have exposure ages of ~1 Ma, in agreement with published data for similar specimens. The exposure age of NWA 10153 (~12.2 Ma) falls in the range of 9-13 Ma reported for other nakhlites. Our preferred age of ~7.3 Ma for NWA 5790 is lower than this range, and it is possible that NWA 5790 represents a distinct ejection event. A Tissint glass sample contains Xe from the Martian atmosphere. Several samples show a remarkably low (21Ne/22Ne)cos ratio < 0.80, as previously observed in a many <span class="hlt">shergottites</span> and in various other rare achondrites. This was explained by solar cosmic ray-produced Ne (SCR Ne) in addition to the commonly found galactic cosmic ray-produced Ne, implying very low preatmospheric shielding and ablation loss. We revisit this by comparing measured (21Ne/22Ne)cos ratios with predictions by cosmogenic nuclide production models. Indeed, several <span class="hlt">shergottites</span>, acalpulcoites/lodranites, angrites (including NWA 7812), and the Brachina-like meteorite LEW 88763 likely contain SCR Ne, as previously postulated for many of them. The SCR contribution may influence the calculation of exposure ages. One likely reason that SCR nuclides are predominantly detected in meteorites from rare classes is because they usually are analyzed for cosmogenic nuclides even if they had a very small (preatmospheric) mass and hence low ablation loss.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015EGUGA..17.1537H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015EGUGA..17.1537H"><span id="translatedtitle">Li<span class="hlt">DAR</span> Vegetation Investigation and Signature Analysis System (LVISA)</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Höfle, Bernhard; Koenig, Kristina; Griesbaum, Luisa; Kiefer, Andreas; Hämmerle, Martin; Eitel, Jan; Koma, Zsófia</p> <p>2015-04-01</p> <p>Our physical environment undergoes constant changes in space and time with strongly varying triggers, frequencies, and magnitudes. Monitoring these environmental changes is crucial to improve our scientific understanding of complex human-environmental interactions and helps us to respond to environmental change by adaptation or mitigation. The three-dimensional (3D) description of the Earth surface features and the detailed monitoring of surface processes using 3D spatial data have gained increasing attention within the last decades, such as in climate change research (e.g., glacier retreat), carbon sequestration (e.g., forest biomass monitoring), precision agriculture and natural hazard management. In all those areas, 3D data have helped to improve our process understanding by allowing quantifying the structural properties of earth surface features and their changes over time. This advancement has been fostered by technological developments and increased availability of 3D sensing systems. In particular, Li<span class="hlt">DAR</span> (light detection and ranging) technology, also referred to as laser scanning, has made significant progress and has evolved into an operational tool in environmental research and geosciences. The main result of Li<span class="hlt">DAR</span> measurements is a highly spatially resolved 3D point cloud. Each point within the Li<span class="hlt">DAR</span> point cloud has a XYZ coordinate associated with it and often additional information such as the strength of the returned backscatter. The point cloud provided by Li<span class="hlt">DAR</span> contains rich geospatial, structural, and potentially biochemical information about the surveyed objects. To deal with the inherently unorganized datasets and the large data volume (frequently millions of XYZ coordinates) of Li<span class="hlt">DAR</span> datasets, a multitude of algorithms for automatic 3D object detection (e.g., of single trees) and physical surface description (e.g., biomass) have been developed. However, so far the exchange of datasets and approaches (i.e., extraction algorithms) among Li<span class="hlt">DAR</span> users</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2016ISPAnIII1..201J&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2016ISPAnIII1..201J&link_type=ABSTRACT"><span id="translatedtitle">Uas Topographic Mapping with Velodyne Li<span class="hlt">DAR</span> Sensor</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Jozkow, G.; Toth, C.; Grejner-Brzezinska, D.</p> <p>2016-06-01</p> <p>Unmanned Aerial System (UAS) technology is nowadays willingly used in small area topographic mapping due to low costs and good quality of derived products. Since cameras typically used with UAS have some limitations, e.g. cannot penetrate the vegetation, Li<span class="hlt">DAR</span> sensors are increasingly getting attention in UAS mapping. Sensor developments reached the point when their costs and size suit the UAS platform, though, Li<span class="hlt">DAR</span> UAS is still an emerging technology. One issue related to using Li<span class="hlt">DAR</span> sensors on UAS is the limited performance of the navigation sensors used on UAS platforms. Therefore, various hardware and software solutions are investigated to increase the quality of UAS Li<span class="hlt">DAR</span> point clouds. This work analyses several aspects of the UAS Li<span class="hlt">DAR</span> point cloud generation performance based on UAS flights conducted with the Velodyne laser scanner and cameras. The attention was primarily paid to the trajectory reconstruction performance that is essential for accurate point cloud georeferencing. Since the navigation sensors, especially Inertial Measurement Units (IMUs), may not be of sufficient performance, the estimated camera poses could allow to increase the robustness of the estimated trajectory, and subsequently, the accuracy of the point cloud. The accuracy of the final UAS Li<span class="hlt">DAR</span> point cloud was evaluated on the basis of the generated DSM, including comparison with point clouds obtained from dense image matching. The results showed the need for more investigation on MEMS IMU sensors used for UAS trajectory reconstruction. The accuracy of the UAS Li<span class="hlt">DAR</span> point cloud, though lower than for point cloud obtained from images, may be still sufficient for certain mapping applications where the optical imagery is not useful.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2005AGUFM.P51A0902D&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2005AGUFM.P51A0902D&link_type=ABSTRACT"><span id="translatedtitle">Assimilation of High 18O/16O Crust by <span class="hlt">Shergottite</span>-Nakhlite-Chassigny (SNC) Magmas on Mars</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Day, J. M.; Taylor, L. A.; Valley, J. W.; Spicuzza, M. J.</p> <p>2005-12-01</p> <p>There is significant geochemical evidence for assimilation of crustal material into sub-aerial, mantle-derived, terrestrial basaltic magmas. Some of the most powerful constraints on crustal assimilation come from oxygen isotope studies, because supracrustal rocks often have distinct 18O/16O ratios resulting from interaction with Earth's hydrosphere. From a planetary perspective, studies of carbonate concretions from meteorite ALH84001 have yielded evidence for low-temperature crustal interaction at or near the surface of its putative parent body, Mars. This finding raises the possibility that crustal assimilation processes may be tracked using oxygen isotopes in combination with geochemical data of other reputed martian (SNC) meteorites. The whole-rock oxygen isotope ratios (Laser fluorination δ18O = +4.21 to +5.85‰ VSMOW) of SNC meteorites, correlate with aspects of their incompatible element chemistry. Some of the oxygen isotope variability may be explained by post-magmatic alteration on Mars or Earth; however, it appears, based on petrographic and geochemical observations, that a number of SNC meteorites, especially <span class="hlt">Shergottites</span>, retain the original whole-rock oxygen isotope values of their magmas prior to crystallisation. Correlations between oxygen isotopes and incompatible element geochemistry are consistent with assimilation of a high-18O/16O, incompatible-element rich, oxidizing crustal component by hot, mantle-derived magmas (δ18O = ~~4.2‰). A crustal component has previously been recognized from Sr-Nd-Os isotope systematics and oxygen fugacity measurements of SNC meteorites. Oxygen isotope evidence from SNC meteorites suggests high-18O/16O crustal contaminants on Mars result from low temperature (< 300°C) interaction with martian hydrosphere. The extent of apparent crustal contamination tracked by oxygen isotopes in SNC meteorites implies that the majority of martian crust may have undergone such interactions. Evidence for assimilation of</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015AdWR...75..105M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015AdWR...75..105M"><span id="translatedtitle">Urban flood modelling combining top-view Li<span class="hlt">DAR</span> data with ground-view SfM observations</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Meesuk, Vorawit; Vojinovic, Zoran; Mynett, Arthur E.; Abdullah, Ahmad F.</p> <p>2015-01-01</p> <p>Remote Sensing technologies are capable of providing high-resolution spatial data needed to set up advanced flood simulation models. Amongst them, aerial Light Detection and Ranging (Li<span class="hlt">DAR</span>) surveys or Airborne Laser Scanner (<span class="hlt">ALS</span>) systems have long been used to provide digital topographic maps. Nowadays, Remote Sensing data are commonly used to create Digital Terrain Models (DTMs) for detailed urban-flood modelling. However, the difficulty of relying on top-view Li<span class="hlt">DAR</span> data only is that it cannot detect whether passages for floodwaters are hidden underneath vegetated areas or beneath overarching structures such as roads, railroads, and bridges. Such (hidden) small urban features can play an important role in urban flood propagation. In this paper, a complex urban area of Kuala Lumpur, Malaysia was chosen as a study area to simulate the extreme flooding event that occurred in 2003. Three different DTMs were generated and used as input for a two-dimensional (2D) urban flood model. A top-view Li<span class="hlt">DAR</span> approach was used to create two DTMs: (i) a standard Li<span class="hlt">DAR</span>-DTM and (ii) a Filtered Li<span class="hlt">DAR</span>-DTM taking into account specific ground-view features. In addition, a Structure from Motion (SfM) approach was used to detect hidden urban features from a sequence of ground-view images; these ground-view SfM data were then combined with top-view Filtered Li<span class="hlt">DAR</span> data to create (iii) a novel Multidimensional Fusion of Views-Digital Terrain Model (MFV-DTM). These DTMs were then used as a basis for the 2D urban flood model. The resulting dynamic flood maps are compared with observations at six measurement locations. It was found that when applying only top-view DTMs as input data, the flood simulation results appear to have mismatches in both floodwater depths and flood propagation patterns. In contrast, when employing the top-ground-view fusion approach (MFV-DTM), the results not only show a good agreement in floodwater depth, but also simulate more correctly the floodwater dynamics around</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011AGUFM.S12A..05S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011AGUFM.S12A..05S"><span id="translatedtitle">Reexamination of Faulting in the Tahoe Basin Using Airborne Li<span class="hlt">DAR</span> Data and Seismic CHIRP Imagery</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Schmauder, G. C.; Kent, G.; Smith, K. D.; Driscoll, N. W.; Maloney, J. M.</p> <p>2011-12-01</p> <p>Faulting across the Tahoe basin has been mapped using a combination of multibeam sonar, airborne Light Detection and Ranging (Li<span class="hlt">DAR</span>), and high-resolution seismic CHIRP imagery. In August 2010, the Tahoe Regional Planning Agency (TRPA) collected 941 square kilometers of airborne Li<span class="hlt">DAR</span> data in the Tahoe basin using a Leica <span class="hlt">ALS</span>50 Phase II Laser system mounted on a Cessna Caravan 208B aircraft; our group was involved with data specification, selection of contractor and data QC. These data have a resolution of 11.82 points per square meter and a vertical accuracy of 3.5 centimeters. The high data resolution has allowed us to map with ease the many fault scarps associated with the three major active fault zones in the Tahoe basin, which include the West Tahoe-Dollar Point fault zone, the Stateline fault, and the Incline Village fault. By using the airborne Li<span class="hlt">DAR</span> data, we were able to identify previously unmapped fault segments throughout the Tahoe basin. Future application of terrestrial Li<span class="hlt">DAR</span> using an I-Site 4400 laser scanner at selected sites will provide better control and resolution of the fault scarp characteristics. This will allow us to not only ground truth the airborne Li<span class="hlt">DAR</span>, but also look for subtle features that may be indicative of dextral motion on faults otherwise displaying predominantly normal displacement. Finally, to refine fault locations beneath Lake Tahoe, Fallen Leaf Lake and Cascade Lake, we collected additional CHIRP imagery using an Edgetech Subscan system, in some cases to groundtruth the new Li<span class="hlt">DAR</span> fault data (i.e., Cascade Lake). By combining these images with the Li<span class="hlt">DAR</span>, multibeam data and new multispectral imagery, we were able to link previously unknown segments of the faults and identify continuity in the individual fault systems. From our results, we have developed a much-improved model of the fault systems within the Lake Tahoe basin. Our model provides us with a better understanding of the tectonic environment of the basin and may help</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015AGUFM.H54A..07H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015AGUFM.H54A..07H"><span id="translatedtitle">Wet Channel Network Extraction based on Li<span class="hlt">DAR</span> Data</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Hooshyar, M.; Kim, S.; Wang, D.; Medeiros, S. C.</p> <p>2015-12-01</p> <p>The temporal dynamics of stream network is vitally important for understanding hydrologic processes including groundwater interactions and hydrograph recessions. However, observations are limited on flowing channel heads, which are usually located in headwater catchments and under canopy. Near infrared Li<span class="hlt">DAR</span> data provides an opportunity to map the flowing channel network owing to the fine spatial resolution, canopy penetration, and strong absorption of the light energy by the water surface. A systematic method is developed herein to map flowing channel networks based on the signal intensity of ground Li<span class="hlt">DAR</span> return, which is lower on water surfaces than on dry surfaces. Based on the selected sample sites where the wetness conditions are known, the signal intensities of ground returns are extracted from the Li<span class="hlt">DAR</span> point data. The frequency distributions of wet surface and dry surface returns are constructed. With the aid of Li<span class="hlt">DAR</span>-based ground elevation, the signal intensity thresholds are identified for mapping flowing channels. The developed method is applied to Lake Tahoe area based on eight Li<span class="hlt">DAR</span> snapshots during recession periods in five watersheds. A power-law relationship between streamflow and flowing channel length during the recession period is derived based on the result.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015AGUFM.B43C0558W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015AGUFM.B43C0558W"><span id="translatedtitle">Biomass Estimation for Individual Trees using Waveform Li<span class="hlt">DAR</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Wang, K.; Kumar, P.; Dutta, D.</p> <p>2015-12-01</p> <p>Vegetation biomass information is important for many ecological models that include terrestrial vegetation in their simulations. Biomass has strong influences on carbon, water, and nutrient cycles. Traditionally biomass estimation requires intensive, and often destructive, field measurements. However, with advances in technology, airborne Li<span class="hlt">DAR</span> has become a convenient tool for acquiring such information on a large scale. In this study, we use infrared full waveform Li<span class="hlt">DAR</span> to estimate biomass information for individual trees in the Sangamon River basin in Illinois, USA. During this process, we also develop automated geolocation calibration algorithms for raw waveform Li<span class="hlt">DAR</span> data. In the summer of 2014, discrete and waveform Li<span class="hlt">DAR</span> data were collected over the Sangamon River basin. Field measurements commonly used in biomass equations such as diameter at breast height and total tree height were also taken for four sites across the basin. Using discrete Li<span class="hlt">DAR</span> data, individual trees are delineated. For each tree, a voxelization methods is applied to all waveforms associated with the tree to result in a pseudo-waveform. By relating biomass extrapolated using field measurements from a training set of trees to waveform metrics for each corresponding tree, we are able to estimate biomass on an individual tree basis. The results can be especially useful as current models increase in resolution.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014AGUFMEP41B3539J','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014AGUFMEP41B3539J"><span id="translatedtitle">Automated Probabilistic Li<span class="hlt">DAR</span> Swath Registration</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Jalobeanu, A.; Gonçalves, G. R.</p> <p>2014-12-01</p> <p>We recently developed a new point cloud registration algorithm. Compared to Iterated Closest Point (ICP) techniques, it is robust to noise and outliers, and easier to use, as it is less sensitive to initial conditions. It minimizes the entropy of the joint point cloud (including intensity attributes to help register areas with poor relief), uses a voxel space and B-Spline interpolation to accelerate computation. A natural application of registration is swath alignment in airborne light detection and ranging (Li<span class="hlt">DAR</span>). Indeed, due to uncertainty in the inertial navigation system (INS), attitude angles are subject to time-dependent errors. Such errors can be understood as a sum of three terms: 1) a global term, or boresight error, which can be addressed using several existing techniques; 2) a low-frequency term, which is modeled as a constant attitude error for regions several hundred meters along-track; 3) a high-frequency term, responsible for corduroy artifacts (not addressed here). We propose to use the new registration algorithm to correct the low-frequency attitude variations. Relative geometric errors are significantly reduced, as pairs of swaths are registered onto each other local corrections. Absolute geometric errors are reduced during a second step, by applying all the corrections together to the entire dataset. We used a test area of 200 km2 in Portugal, with a density of 3-4 pts/m2. The point clouds were derived from waveform data, and include predictive range uncertainties estimated within a Bayesian framework. The data collection was supported by FCT and FEDER as part of the AutoProbaDTM research project (2009-2012). Modeling and reducing geometric error helps build consistent uncertainty maps. After correction, residual errors are taken into account in the final 3D error budget. For gridded elevation models a vertical uncertainty map is computed. Finally, it is possible to use the inter-swath registration parameters to estimate the distribution of</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016SPIE.9901E..10D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016SPIE.9901E..10D"><span id="translatedtitle">Application of Li<span class="hlt">DAR</span>'s multiple attributes for wetland classification</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Ding, Qiong; Ji, Shengyue; Chen, Wu</p> <p>2016-03-01</p> <p>Wetlands have received intensive interdisciplinary attention as a unique ecosystem and valuable resources. As a new technology, the airborne Li<span class="hlt">DAR</span> system has been applied in wetland research these years. However, most of the studies used only one or two Li<span class="hlt">DAR</span> observations to extract either terrain or vegetation in wetlands. This research aims at integrating Li<span class="hlt">DAR</span>'s multiple attributes (DSM, DTM, off-ground features, Slop map, multiple pulse returns, and normalized intensity) to improve mapping and classification of wetlands based on a multi-level object-oriented classification method. By using this method, we are able to classify the Yellow River Delta wetland into eight classes with overall classification accuracy of 92.5%</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010AGUFMED23B0723R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010AGUFMED23B0723R"><span id="translatedtitle">Integrating Li<span class="hlt">DAR</span> Data into Earth Science Education</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Robinson, S. E.; Arrowsmith, R.; de Groot, R. M.; Crosby, C. J.; Whitesides, A. S.; Colunga, J.</p> <p>2010-12-01</p> <p>The use of high-resolution topography derived from Light Detection and Ranging (Li<span class="hlt">DAR</span>) in the study of active tectonics is widespread and has become an indispensable tool to better understand earthquake hazards. For this reason and the spectacular representation of the phenomena the data provide, it is appropriate to integrate these data into the Earth science education curriculum. A collaboration between Arizona State University, the OpenTopography Facility, and the Southern California Earthquake Center are developing, three earth science education products to inform students and other audiences about Li<span class="hlt">DAR</span> and its application to active tectonics research. First, a 10-minute introductory video titled Li<span class="hlt">DAR</span>: Illuminating Earthquakes was produced and is freely available online through the OpenTopography portal and SCEC. The second product is an update and enhancement of the Wallace Creek Interpretive Trail website (www.scec.org/wallacecreek). Li<span class="hlt">DAR</span> topography data products have been added along with the development of a virtual tour of the offset channels at Wallace Creek using the B4 Li<span class="hlt">DAR</span> data within the Google Earth environment. The virtual tour to Wallace Creek is designed as a lab activity for introductory undergraduate geology courses to increase understanding of earthquake hazards through exploration of the dramatic offset created by the San Andreas Fault (SAF) at Wallace Creek and Global Positioning System-derived displacements spanning the SAF at Wallace Creek . This activity is currently being tested in courses at Arizona State University. The goal of the assessment is to measure student understanding of plate tectonics and earthquakes after completing the activity. Including high-resolution topography Li<span class="hlt">DAR</span> data into the earth science education curriculum promotes understanding of plate tectonics, faults, and other topics related to earthquake hazards.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010PhDT.......215M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010PhDT.......215M"><span id="translatedtitle">Modeling loblolly pine dominant height using airborne Li<span class="hlt">DAR</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Maceyka, Andy</p> <p></p> <p>The dominant height of 73 georeferenced field sample plots were modeled from various canopy height metrics derived by means of a small-footprint laser scanning technology, known as light detection and ranging (or just Li<span class="hlt">DAR</span>), over young and mature forest stands using regression analysis. Li<span class="hlt">DAR</span> plot metrics were regressed against field measured dominant height using Best Subsets Regression to reduce the number of models. From those models, regression assumptions were evaluated to determine which model was actually the best. The best model included the 1st and 90th height percentiles as predictors and explained 95% of the variance in average dominant height.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013EGUGA..1510245K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013EGUGA..1510245K"><span id="translatedtitle">Similarity and Complementarity of Airborne and Terrestrial Li<span class="hlt">DAR</span> Data in High Mountain Regions</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kamp, Nicole; Glira, Philipp; Pfeifer, Norbert</p> <p>2013-04-01</p> <p> airborne to the terrestrial data (or vice versa) without introducing systematic errors caused by the above mentioned differences. A workflow for this analysis is established with command line processing of the point clouds using OPALS (Orientation and Processing of Airborne Laser Scanning data, Vienna University of Technology). For further processing of the data, it is necessary to adjust the different scans by using least squares matching of surfaces to improve the orientation of the <span class="hlt">ALS</span> and TLS data. Handling of the terrestrial Li<span class="hlt">DAR</span> data with its very high point density and the data filtering to minimize errors and artefacts turned out to be the biggest challenges. After a relative and absolute orientation of the TLS scans with the help of GNSS spheres (see P. Glira, ESSI1.5), the data are processed in order to make it comparable with the airborne Li<span class="hlt">DAR</span> scans. Different ranges and consequential different footprint sizes and a big variance of the point densities have to be considered. Therefore the application of different filter and interpolation methods is important to get the best results and in further consequence to calculate an ideal Digital Terrain Model (DTM), which provides a good input dataset for future modelling of the geomorphic processes in the PROSA study area around the Gepatschferner.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_6");'>6</a></li> <li><a href="#" onclick='return showDiv("page_7");'>7</a></li> <li class="active"><span>8</span></li> <li><a href="#" onclick='return showDiv("page_9");'>9</a></li> <li><a href="#" onclick='return showDiv("page_10");'>10</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_8 --> <div id="page_9" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_7");'>7</a></li> <li><a href="#" onclick='return showDiv("page_8");'>8</a></li> <li class="active"><span>9</span></li> <li><a href="#" onclick='return showDiv("page_10");'>10</a></li> <li><a href="#" onclick='return showDiv("page_11");'>11</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="161"> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.gpo.gov/fdsys/pkg/CFR-2014-title47-vol2/pdf/CFR-2014-title47-vol2-sec25-401.pdf','CFR2014'); return false;" href="https://www.gpo.gov/fdsys/pkg/CFR-2014-title47-vol2/pdf/CFR-2014-title47-vol2-sec25-401.pdf"><span id="translatedtitle">47 CFR 25.401 - Satellite <span class="hlt">DARS</span> applications subject to competitive bidding.</span></a></p> <p><a target="_blank" href="http://www.gpo.gov/fdsys/browse/collectionCfr.action?selectedYearFrom=2014&page.go=Go">Code of Federal Regulations, 2014 CFR</a></p> <p></p> <p>2014-10-01</p> <p>... 47 Telecommunication 2 2014-10-01 2014-10-01 false Satellite <span class="hlt">DARS</span> applications subject to...) COMMON CARRIER SERVICES SATELLITE COMMUNICATIONS Competitive Bidding Procedures for <span class="hlt">DARS</span> § 25.401 Satellite <span class="hlt">DARS</span> applications subject to competitive bidding. Mutually exclusive initial applications for...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.gpo.gov/fdsys/pkg/CFR-2013-title47-vol2/pdf/CFR-2013-title47-vol2-sec25-401.pdf','CFR2013'); return false;" href="https://www.gpo.gov/fdsys/pkg/CFR-2013-title47-vol2/pdf/CFR-2013-title47-vol2-sec25-401.pdf"><span id="translatedtitle">47 CFR 25.401 - Satellite <span class="hlt">DARS</span> applications subject to competitive bidding.</span></a></p> <p><a target="_blank" href="http://www.gpo.gov/fdsys/browse/collectionCfr.action?selectedYearFrom=2013&page.go=Go">Code of Federal Regulations, 2013 CFR</a></p> <p></p> <p>2013-10-01</p> <p>... 47 Telecommunication 2 2013-10-01 2013-10-01 false Satellite <span class="hlt">DARS</span> applications subject to...) COMMON CARRIER SERVICES SATELLITE COMMUNICATIONS Competitive Bidding Procedures for <span class="hlt">DARS</span> § 25.401 Satellite <span class="hlt">DARS</span> applications subject to competitive bidding. Mutually exclusive initial applications for...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.gpo.gov/fdsys/pkg/CFR-2011-title47-vol2/pdf/CFR-2011-title47-vol2-sec25-401.pdf','CFR2011'); return false;" href="https://www.gpo.gov/fdsys/pkg/CFR-2011-title47-vol2/pdf/CFR-2011-title47-vol2-sec25-401.pdf"><span id="translatedtitle">47 CFR 25.401 - Satellite <span class="hlt">DARS</span> applications subject to competitive bidding.</span></a></p> <p><a target="_blank" href="http://www.gpo.gov/fdsys/browse/collectionCfr.action?selectedYearFrom=2011&page.go=Go">Code of Federal Regulations, 2011 CFR</a></p> <p></p> <p>2011-10-01</p> <p>... 47 Telecommunication 2 2011-10-01 2011-10-01 false Satellite <span class="hlt">DARS</span> applications subject to...) COMMON CARRIER SERVICES SATELLITE COMMUNICATIONS Competitive Bidding Procedures for <span class="hlt">DARS</span> § 25.401 Satellite <span class="hlt">DARS</span> applications subject to competitive bidding. Mutually exclusive initial applications for...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.gpo.gov/fdsys/pkg/CFR-2012-title47-vol2/pdf/CFR-2012-title47-vol2-sec25-401.pdf','CFR2012'); return false;" href="https://www.gpo.gov/fdsys/pkg/CFR-2012-title47-vol2/pdf/CFR-2012-title47-vol2-sec25-401.pdf"><span id="translatedtitle">47 CFR 25.401 - Satellite <span class="hlt">DARS</span> applications subject to competitive bidding.</span></a></p> <p><a target="_blank" href="http://www.gpo.gov/fdsys/browse/collectionCfr.action?selectedYearFrom=2012&page.go=Go">Code of Federal Regulations, 2012 CFR</a></p> <p></p> <p>2012-10-01</p> <p>... 47 Telecommunication 2 2012-10-01 2012-10-01 false Satellite <span class="hlt">DARS</span> applications subject to...) COMMON CARRIER SERVICES SATELLITE COMMUNICATIONS Competitive Bidding Procedures for <span class="hlt">DARS</span> § 25.401 Satellite <span class="hlt">DARS</span> applications subject to competitive bidding. Mutually exclusive initial applications for...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.gpo.gov/fdsys/pkg/CFR-2010-title47-vol2/pdf/CFR-2010-title47-vol2-sec25-401.pdf','CFR'); return false;" href="https://www.gpo.gov/fdsys/pkg/CFR-2010-title47-vol2/pdf/CFR-2010-title47-vol2-sec25-401.pdf"><span id="translatedtitle">47 CFR 25.401 - Satellite <span class="hlt">DARS</span> applications subject to competitive bidding.</span></a></p> <p><a target="_blank" href="http://www.gpo.gov/fdsys/browse/collectionCfr.action?selectedYearFrom=2010&page.go=Go">Code of Federal Regulations, 2010 CFR</a></p> <p></p> <p>2010-10-01</p> <p>... 47 Telecommunication 2 2010-10-01 2010-10-01 false Satellite <span class="hlt">DARS</span> applications subject to...) COMMON CARRIER SERVICES SATELLITE COMMUNICATIONS Competitive Bidding Procedures for <span class="hlt">DARS</span> § 25.401 Satellite <span class="hlt">DARS</span> applications subject to competitive bidding. Mutually exclusive initial applications for...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ars.usda.gov/research/publications/Publications.htm?seq_no_115=219998','TEKTRAN'); return false;" href="http://www.ars.usda.gov/research/publications/Publications.htm?seq_no_115=219998"><span id="translatedtitle"><span class="hlt">DAr</span>T marker development and applications in oat</span></a></p> <p><a target="_blank" href="http://www.ars.usda.gov/services/TekTran.htm">Technology Transfer Automated Retrieval System (TEKTRAN)</a></p> <p></p> <p></p> <p>Progress of genomic research in oat has been limited by a lack of common markers and consensus maps that would provide integration platforms for structural genomic analysis. Diversity Array Technology (<span class="hlt">DAr</span>T) is a strategy that provides a high density of molecular markers that can be tested in par...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ars.usda.gov/research/publications/Publications.htm?seq_no_115=264067','TEKTRAN'); return false;" href="http://www.ars.usda.gov/research/publications/Publications.htm?seq_no_115=264067"><span id="translatedtitle">Modeling low-height vegetation with airborne Li<span class="hlt">DAR</span></span></a></p> <p><a target="_blank" href="http://www.ars.usda.gov/services/TekTran.htm">Technology Transfer Automated Retrieval System (TEKTRAN)</a></p> <p></p> <p></p> <p>Low-height vegetation, common in semiarid regions, is difficult to characterize with Li<span class="hlt">DAR</span> (Light Detection and Ranging) due to similarities, in time and space, of the point returns of vegetation and ground. Other complications may occur due to the low-height vegetation structural characteristics a...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20150012722','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20150012722"><span id="translatedtitle">Features of Point Clouds Synthesized from Multi-View ALOS/PRISM Data and Comparisons with Li<span class="hlt">DAR</span> Data in Forested Areas</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Ni, Wenjian; Ranson, Kenneth Jon; Zhang, Zhiyu; Sun, Guoqing</p> <p>2014-01-01</p> <p>Li<span class="hlt">DAR</span> waveform data from airborne Li<span class="hlt">DAR</span> scanners (<span class="hlt">ALS</span>) e.g. the Land Vegetation and Ice Sensor (LVIS) havebeen successfully used for estimation of forest height and biomass at local scales and have become the preferredremote sensing dataset. However, regional and global applications are limited by the cost of the airborne LiDARdata acquisition and there are no available spaceborne Li<span class="hlt">DAR</span> systems. Some researchers have demonstrated thepotential for mapping forest height using aerial or spaceborne stereo imagery with very high spatial resolutions.For stereo imageswith global coverage but coarse resolution newanalysis methods need to be used. Unlike mostresearch based on digital surface models, this study concentrated on analyzing the features of point cloud datagenerated from stereo imagery. The synthesizing of point cloud data from multi-view stereo imagery increasedthe point density of the data. The point cloud data over forested areas were analyzed and compared to small footprintLi<span class="hlt">DAR</span> data and large-footprint Li<span class="hlt">DAR</span> waveform data. The results showed that the synthesized point clouddata from ALOSPRISM triplets produce vertical distributions similar to Li<span class="hlt">DAR</span> data and detected the verticalstructure of sparse and non-closed forests at 30mresolution. For dense forest canopies, the canopy could be capturedbut the ground surface could not be seen, so surface elevations from other sourceswould be needed to calculatethe height of the canopy. A canopy height map with 30 m pixels was produced by subtracting nationalelevation dataset (NED) fromthe averaged elevation of synthesized point clouds,which exhibited spatial featuresof roads, forest edges and patches. The linear regression showed that the canopy height map had a good correlationwith RH50 of LVIS data with a slope of 1.04 and R2 of 0.74 indicating that the canopy height derived fromPRISM triplets can be used to estimate forest biomass at 30 m resolution.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2016E%26PSL.444....1D&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2016E%26PSL.444....1D&link_type=ABSTRACT"><span id="translatedtitle">Variable microstructural response of baddeleyite to shock metamorphism in young basaltic <span class="hlt">shergottite</span> NWA 5298 and improved U-Pb dating of Solar System events</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Darling, James R.; Moser, Desmond E.; Barker, Ivan R.; Tait, Kim T.; Chamberlain, Kevin R.; Schmitt, Axel K.; Hyde, Brendt C.</p> <p>2016-06-01</p> <p>The accurate dating of igneous and impact events is vital for the understanding of Solar System evolution, but has been hampered by limited knowledge of how shock metamorphism affects mineral and whole-rock isotopic systems used for geochronology. Baddeleyite (monoclinic ZrO2) is a refractory mineral chronometer of great potential to date these processes due to its widespread occurrence in achondrites and robust U-Pb isotopic systematics, but there is little understanding of shock-effects on this phase. Here we present new nano-structural measurements of baddeleyite grains in a thin-section of the highly-shocked basaltic <span class="hlt">shergottite</span> Northwest Africa (NWA) 5298, using high-resolution electron backscattered diffraction (EBSD) and scanning transmission electron microscopy (STEM) techniques, to investigate shock-effects and their linkage with U-Pb isotopic disturbance that has previously been documented by in-situ U-Pb isotopic analyses. The shock-altered state of originally igneous baddeleyite grains is highly variable across the thin-section and often within single grains. Analyzed grains range from those that preserve primary (magmatic) twinning and trace-element zonation (baddeleyite shock Group 1), to quasi-amorphous ZrO2 (Group 2) and to recrystallized micro-granular domains of baddeleyite (Group 3). These groups correlate closely with measured U-Pb isotope compositions. Primary igneous features in Group 1 baddeleyites (n = 5) are retained in high shock impedance grain environments, and an average of these grains yields a revised late-Amazonian magmatic crystallization age of 175 ± 30 Ma for this <span class="hlt">shergottite</span>. The youngest U-Pb dates occur from Group 3 recrystallized nano- to micro-granular baddeleyite grains, indicating that it is post-shock heating and new mineral growth that drives much of the isotopic disturbance, rather than just shock deformation and phase transitions. Our data demonstrate that a systematic multi-stage microstructural evolution in</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015E%26PSL.418...91P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015E%26PSL.418...91P"><span id="translatedtitle">Tracking the source of the enriched martian meteorites in olivine-hosted melt inclusions of two depleted <span class="hlt">shergottites</span>, Yamato 980459 and Tissint</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Peters, T. J.; Simon, J. I.; Jones, J. H.; Usui, T.; Moriwaki, R.; Economos, R. C.; Schmitt, A. K.; McKeegan, K. D.</p> <p>2015-05-01</p> <p>The apparent lack of plate tectonics on all terrestrial planets other than Earth has been used to support the notion that for most planets, once a primitive crust forms, the crust and mantle evolve geochemically-independent through time. This view has had a particularly large impact on models for the evolution of Mars and its silicate interior. Recent data indicating a greater potential that there may have been exchange between the martian crust and mantle has led to a search for additional geochemical evidence to support the alternative hypothesis, that some mechanism of crustal recycling may have operated early in the history of Mars. In order to study the most juvenile melts available to investigate martian mantle source(s) and melting processes, the trace element compositions of olivine-hosted melt inclusions for two incompatible-element-depleted olivine-phyric <span class="hlt">shergottites</span>, Yamato 980459 (Y98) and Tissint, and the interstitial glass of Y98, have been measured by Secondary Ionization Mass Spectrometry (SIMS). Chondrite-normalized Rare Earth Element (REE) patterns for both Y98 and Tissint melt inclusions, and the Y98 interstitial glass, are characteristically light-REE depleted and parallel those of their host rock. For Y98, a clear flattening and upward inflection of La and Ce, relative to predictions based on middle and heavier REE, provides evidence for involvement of an enriched component early in their magmatic history; either inherited from a metasomatized mantle or crustal source, early on and prior to extensive host crystallization. Comparing these melt inclusion and interstitial glass analyses to existing melt inclusion and whole-rock data sets for the <span class="hlt">shergottite</span> meteorite suite, defines mixing relationships between depleted and enriched end members, analogous to mixing relationships between whole rock Sr and Nd isotopic measurements. When considered in light of their petrologic context, the origin of these trace element enriched and isotopically</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015NCimC..38...84C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015NCimC..38...84C"><span id="translatedtitle">High-intensity cyclotron for the Iso<span class="hlt">DAR</span> experiment</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Campo, D.; IsoDAR Collaboration</p> <p>2015-03-01</p> <p>The Iso<span class="hlt">DAR</span> experiment is the MIT proposal to investigate about several neutrino properties, in order to explain some anomalies experimentally observed. It requires 10mA of proton beam at the energy of 60MeV to produce a high-intensity electron antineutrino flux from the production and the decay of 8Li: it is an ambitious goal for the accelerator design, due also to the fact that the machine has to be placed near a neutrino detector, like KAMLAND or WATCHMAN, located in underground sites. A compact cyclotron able to accelerate H2+ molecule beam up to energy of 60MeV/amu is under study. The critical issues of this machine concern the beam injection due to the effects of space charge, the efficiency of the beam extraction and the technical solutions needed to the machine assembly. Here, the innovative solutions and the preliminary results achieved by the Iso<span class="hlt">DAR</span> team are discussed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2015SPIE.9477E..0FV&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2015SPIE.9477E..0FV&link_type=ABSTRACT"><span id="translatedtitle">Volume component analysis for classification of Li<span class="hlt">DAR</span> data</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Varney, Nina M.; Asari, Vijayan K.</p> <p>2015-03-01</p> <p>One of the most difficult challenges of working with Li<span class="hlt">DAR</span> data is the large amount of data points that are produced. Analysing these large data sets is an extremely time consuming process. For this reason, automatic perception of Li<span class="hlt">DAR</span> scenes is a growing area of research. Currently, most Li<span class="hlt">DAR</span> feature extraction relies on geometrical features specific to the point cloud of interest. These geometrical features are scene-specific, and often rely on the scale and orientation of the object for classification. This paper proposes a robust method for reduced dimensionality feature extraction of 3D objects using a volume component analysis (VCA) approach.1 This VCA approach is based on principal component analysis (PCA). PCA is a method of reduced feature extraction that computes a covariance matrix from the original input vector. The eigenvectors corresponding to the largest eigenvalues of the covariance matrix are used to describe an image. Block-based PCA is an adapted method for feature extraction in facial images because PCA, when performed in local areas of the image, can extract more significant features than can be extracted when the entire image is considered. The image space is split into several of these blocks, and PCA is computed individually for each block. This VCA proposes that a Li<span class="hlt">DAR</span> point cloud can be represented as a series of voxels whose values correspond to the point density within that relative location. From this voxelized space, block-based PCA is used to analyze sections of the space where the sections, when combined, will represent features of the entire 3-D object. These features are then used as the input to a support vector machine which is trained to identify four classes of objects, vegetation, vehicles, buildings and barriers with an overall accuracy of 93.8%</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2012AGUFM.G23A0886G&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2012AGUFM.G23A0886G&link_type=ABSTRACT"><span id="translatedtitle">Compact Adaptable Mobile Li<span class="hlt">DAR</span> System Deployment</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Glennie, C. L.; Brooks, B. A.; Ericksen, T. L.; Hudnut, K. W.; Foster, J. H.; Hauser, D.; Avery, J.</p> <p>2012-12-01</p> <p>Airborne Li<span class="hlt">DAR</span> (LIght Detection And Ranging) systems have become a standard mechanism for acquiring dense high-precision topography, making it possible to perform large scale documentation (100's of km2) per day at spatial scales as fine as a few decimeters horizontally and a few centimeters vertically. However, current airborne and terrestrial Li<span class="hlt">DAR</span> systems suffer from a number of drawbacks. They are expensive, bulky, require significant power supplies, and are often optimized for use in only one type of mobility platform. It would therefore be advantageous to design a lightweight, compact and relatively inexpensive multipurpose Li<span class="hlt">DAR</span> and imagery system that could be used from a variety of mobility platforms - both terrestrial and airborne. The system should be quick and easy to deploy, and require a minimum amount of existing infrastructure for operational support. With these goals in mind, our research teams have developed a prototype field deployable compact dynamic laser scanning system that is configured for use on a variety of mobility platforms, including backpack wearable, as well as unmanned aerial vehicles (e.g. balloons & helicopters) and small off-road vehicles such as ATV's. The system is small, self-contained, relatively inexpensive, and easy to deploy. The first version of this multipurpose Li<span class="hlt">DAR</span> system has been successfully tested in both backpack configuration and on a tethered flight attached to a helium balloon. We will present system design and development details, along with field experiences and a detailed accuracy analysis of the acquired point clouds which show that accuracy of 3-5 cm (1 sigma) vertical can be achieved in both backpack and balloon modalities.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2016EGUGA..1817935S&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2016EGUGA..1817935S&link_type=ABSTRACT"><span id="translatedtitle">Coastal and tidal landform detection from high resolution topobathymetric Li<span class="hlt">DAR</span> data</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Skovgaard Andersen, Mikkel; Al-Hamdani, Zyad; Steinbacher, Frank; Rolighed Larsen, Laurids; Brandbyge Ernstsen, Verner</p> <p>2016-04-01</p> <p>Coastal and tidal environments are valuable ecosystems, which, however, are under pressure in many areas around the world due to globalisation and/or climate change. Detailed mapping of these environments is required in order to manage the coastal zone in a sustainable way. However, historically these transition zones between land and water are difficult or even impossible to map and investigate in high spatial resolution due to the challenging environmental conditions. The new generation of airborne topobathymetric light detection and ranging (Li<span class="hlt">DAR</span>) potentially enables full-coverage and high-resolution mapping of these land-water transition zones. We have carried out topobathymetric Li<span class="hlt">DAR</span> surveys in the Knudedyb tidal inlet system, a coastal environment in the Danish Wadden Sea which is part of the Wadden Sea National Park and UNESCO World Heritage. Detailed digital elevation models (DEMs) with a grid cell size of 0.5 m x 0.5 m were generated from the Li<span class="hlt">DAR</span> point cloud with a mean point density in the order of 20 points/m2. The DEM was analysed morphometrically using a modification of the tool Benthic Terrain Modeler (BTM) developed by Wright et <span class="hlt">al</span>. (2005). Initially, stage (the elevation in relation to tidal range) was used to divide the area of investigation into the different tidal zones, i.e. subtidal, intertidal and supratidal. Subsequently, morphometric units were identified and characterised by a combination of statistical neighbourhood analysis with varying window sizes (using the Bathymetric Positioning Index (BPI) from the BTM, moving average and standard deviation), slope parameters and area/perimeter ratios. Finally, these morphometric units were classified into six different types of landforms based on their stage and morphometric characteristics, i.e. either subtidal channel, intertidal flat, intertidal creek, linear bar, swash bar or beach dune. We hereby demonstrate the potential of using airborne topobathymetric Li<span class="hlt">DAR</span> for seamless mapping of land</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015IJAEO..43...92S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015IJAEO..43...92S"><span id="translatedtitle">A new 500-m resolution map of canopy height for Amazon forest using spaceborne Li<span class="hlt">DAR</span> and cloud-free MODIS imagery</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Sawada, Yoshito; Suwa, Rempei; Jindo, Keiji; Endo, Takahiro; Oki, Kazuo; Sawada, Haruo; Arai, Egidio; Shimabukuro, Yosio Edemir; Celes, Carlos Henrique Souza; Campos, Moacir Alberto Assis; Higuchi, Francisco Gasparetto; Lima, Adriano José Nogueira; Higuchi, Niro; Kajimoto, Takuya; Ishizuka, Moriyoshi</p> <p>2015-12-01</p> <p>In the present study, we aimed to map canopy heights in the Brazilian Amazon mainly on the basis of spaceborne Li<span class="hlt">DAR</span> and cloud-free MODIS imagery with a new method (the Self-Organizing Relationships method) for spatial modeling of the Li<span class="hlt">DAR</span> footprint. To evaluate the general versatility, we compared the created canopy height map with two different canopy height estimates on the basis of our original field study plots (799 plots located in eight study sites) and a previously developed canopy height map. The compared canopy height estimates were obtained by: (1) a stem diameter at breast height (D) - tree height (H) relationship specific to each site on the basis of our original field study, (2) a previously developed D-H model involving environmental and structural factors as explanatory variables (Feldpausch et <span class="hlt">al</span>., 2011), and (3) a previously developed canopy height map derived from the spaceborne Li<span class="hlt">DAR</span> data with different spatial modeling method and explanatory variables (Simard et <span class="hlt">al</span>., 2011). As a result, our canopy height map successfully detected a spatial distribution pattern in canopy height estimates based on our original field study data (r = 0.845, p = 8.31 × 10-3) though our canopy height map showed a poor correlation (r = 0.563, p = 0.146) with the canopy height estimate based on a previously developed model by Feldpausch et <span class="hlt">al</span>. (2011). We also confirmed that the created canopy height map showed a similar pattern with the previously developed canopy height map by Simard et <span class="hlt">al</span>. (2011). It was concluded that the use of the spaceborne Li<span class="hlt">DAR</span> data provides a sufficient accuracy in estimating the canopy height at regional scale.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015EGUGA..1714243W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015EGUGA..1714243W"><span id="translatedtitle">Li<span class="hlt">DAR</span> observation of the flow structure in typhoons</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Wu, Yu-Ting; Hsuan, Chung-Yao; Lin, Ta-Hui</p> <p>2015-04-01</p> <p>Taiwan is subject to 3.4 landfall typhoons each year in average, generally occurring in the third quarter of every year (July-September). Understanding of boundary-layer turbulence characteristics of a typhoon is needed to ensure the safety of both onshore and offshore wind turbines used for power generation. In this study, a floating Li<span class="hlt">DAR</span> (Light Detection and Ranging) was deployed in a harbor to collect data of wind turbulence, atmospheric pressure, and temperature in three typhoon events (Matmo typhoon, Soulik typhoon, Trami typhoon). Data collected from the floating Li<span class="hlt">DAR</span> and from meteorological stations located at Taipei, Taichung and Kaohsiung are adopted to analyse the wind turbulence characteristics in the three typhoon events. The measurement results show that the maximum 10-min average wind speed measured with the floating Li<span class="hlt">DAR</span> is up to 24 m/s at a height of 200 m. Compared with other normal days, the turbulence intensity is lower in the three typhoon events where the wind speed has a rapid increase. Changes of wind direction take place clearly as the typhoons cross Taiwan from East to West. Within the crossing intervals, the vertical momentum flux is observed to have a significant pattern with both upward and downward propagating waves which are relevant to the flow structure of the typhoons.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010SPIE.7835E..03A','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010SPIE.7835E..03A"><span id="translatedtitle">Rapid topographic and bathymetric reconnaissance using airborne Li<span class="hlt">DAR</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Axelsson, Andreas</p> <p>2010-10-01</p> <p>Today airborne Li<span class="hlt">DAR</span> (Light Detection And Ranging) systems has gained acceptance as a powerful tool to rapidly collect invaluable information to assess the impact from either natural disasters, such as hurricanes, earthquakes and flooding, or human inflicted disasters such as terrorist/enemy activities. Where satellite based imagery provides an excellent tool to remotely detect changes in the environment, the Li<span class="hlt">DAR</span> systems, being active remote sensors, provide an unsurpassed method to quantify these changes. The strength of the active laser based systems is especially evident in areas covered by occluding vegetation or in the shallow coastal zone as the laser can penetrate the vegetation or water body to unveil what is below. The purpose of this paper is to address the task to survey complex areas with help of the state-of-the-art airborne Li<span class="hlt">DAR</span> systems and also discuss scenarios where the method is used today and where it may be used tomorrow. Regardless if it is a post-hurricane survey or a preparation stage for a landing operation in unchartered waters, it is today possible to collect, process and present a dense 3D model of the area of interest within just a few hours from deployment. By utilizing the advancement in processing power and wireless network capabilities real-time presentation would be feasible.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010Geomo.118..213L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010Geomo.118..213L"><span id="translatedtitle">Rockfall hazard analysis using Li<span class="hlt">DAR</span> and spatial modeling</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Lan, Hengxing; Martin, C. Derek; Zhou, Chenghu; Lim, Chang Ho</p> <p>2010-05-01</p> <p>Rockfalls have been significant geohazards along the Canadian Class 1 Railways (CN Rail and CP Rail) since their construction in the late 1800s. These rockfalls cause damage to infrastructure, interruption of business, and environmental impacts, and their occurrence varies both spatially and temporally. The proactive management of these rockfall hazards requires enabling technologies. This paper discusses a hazard assessment strategy for rockfalls along a section of a Canadian railway using Li<span class="hlt">DAR</span> and spatial modeling. Li<span class="hlt">DAR</span> provides accurate topographical information of the source area of rockfalls and along their paths. Spatial modeling was conducted using Rockfall Analyst, a three dimensional extension to GIS, to determine the characteristics of the rockfalls in terms of travel distance, velocity and energy. Historical rockfall records were used to calibrate the physical characteristics of the rockfall processes. The results based on a high-resolution digital elevation model from a Li<span class="hlt">DAR</span> dataset were compared with those based on a coarse digital elevation model. A comprehensive methodology for rockfall hazard assessment is proposed which takes into account the characteristics of source areas, the physical processes of rockfalls and the spatial attribution of their frequency and energy.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015AGUFM.B52A..07F','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015AGUFM.B52A..07F"><span id="translatedtitle">Increasing the Efficiency of Li<span class="hlt">DAR</span> Based Forest Inventories: A Novel Approach for Integrating Variable Radius Inventory Plots with Li<span class="hlt">DAR</span> Data.</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Falkowski, M. J.; Fekety, P.; Silva, C. A.; Hudak, A. T.</p> <p>2015-12-01</p> <p>Li<span class="hlt">DAR</span> data are increasingly applied to support forest inventory and assessment across a variety of spatial scales. Typically this is achieved by integrating Li<span class="hlt">DAR</span> data with forest inventory collected at fixed radius forest inventory plots. A well-designed forest inventory, one that covers the full range of structural and compositional variation across the forest of interest, is costly especially when collecting fixed radius plot data. Variable radius plots offer an alternative inventory protocol that is more efficient in terms of both time and money. However, integrating variable radius plot data with Li<span class="hlt">DAR</span> data is problematic because the plots have unknown sizes that vary with variation in tree size. This leads to a spatial mismatch between Li<span class="hlt">DAR</span> metrics (e.g., mean height, canopy cover, density, etc.) and plot data, which ultimately translates into errors in Li<span class="hlt">DAR</span> derived forest inventory predictions. We propose and evaluate and novel approach for integrating variable radius plot data into a Li<span class="hlt">DAR</span> based forest inventories in two different forest systems, one in the inland northwest and another in the northern lakes states of the USA. The novel approach calculates Li<span class="hlt">DAR</span> metrics by weighting the point cloud proportional to return height, mimicking the way in which variable radius plot data weights tree measurements by tree size. This could increase inventory sampling efficiency, allowing for the collection of a greater number of inventory plots, and ultimately improve the performance of Li<span class="hlt">DAR</span> based inventories.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010JPRS...65..369K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010JPRS...65..369K"><span id="translatedtitle">Range and AGC normalization in airborne discrete-return Li<span class="hlt">DAR</span> intensity data for forest canopies</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Korpela, Ilkka; Ørka, Hans Ole; Hyyppä, Juha; Heikkinen, Ville; Tokola, Timo</p> <p></p> <p>Recently, the intensity characteristics of discrete-return Li<span class="hlt">DAR</span> sensors were studied for vegetation classification. We examined two normalization procedures affecting Li<span class="hlt">DAR</span> intensity through the scanning geometry and the system settings, namely, range normalization and the effects of the automatic gain control (AGC) in the Optech ALTM3100 and Leica <span class="hlt">ALS</span>50-II sensors. Range normalization corresponds to weighting of the observed intensities with the term (, where R is the range, R is a mean reference range, and a∈[2,4] is the exponent that is, according to theory, dependent on the target geometry. Li<span class="hlt">DAR</span> points belonging to individual tree crowns were extracted for 13 887 trees in southern Finland. The coefficient of variation (CV) of the intensity was analyzed for a range of values of exponent a. The tree species classification performance using 13 intensity variables was also used for sensitivity analysis of the effect of a. The results were in line with the established theory, since the optimal level of a was lower (a≈2) for trees with large or clumped leaves and higher (a≈3) for diffuse coniferous crowns. Different echo groups also showed varying responses. Single-return pulses that represented strong reflections had a lower optimal value of a than the first and all echoes in a pulse. The gain in classification accuracy from the optimal selection of the exponent was 2%-3%, and the optimum for classification was different from that obtained using the CV analysis. In the <span class="hlt">ALS</span>50-II sensor, the combined and optimized AGC and R normalizations had a notably larger effect (6%-9%) on classification accuracy. Our study demonstrates the ambiguity of R normalization in vegetation canopies.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_7");'>7</a></li> <li><a href="#" onclick='return showDiv("page_8");'>8</a></li> <li class="active"><span>9</span></li> <li><a href="#" onclick='return showDiv("page_10");'>10</a></li> <li><a href="#" onclick='return showDiv("page_11");'>11</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_9 --> <div id="page_10" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_8");'>8</a></li> <li><a href="#" onclick='return showDiv("page_9");'>9</a></li> <li class="active"><span>10</span></li> <li><a href="#" onclick='return showDiv("page_11");'>11</a></li> <li><a href="#" onclick='return showDiv("page_12");'>12</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="181"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19970019937','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19970019937"><span id="translatedtitle">Constraints on Martian Differentiation Processes from Rb-Sr and Sm-Nd Isotopic Analyses of the Basaltic <span class="hlt">Shergottite</span> QUE 94201</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Borg, Lars E.; Nyquist, Larry E.; Taylor, Larry A.; Wiesmann, Henry; Shih, Chi-Y.</p> <p>1997-01-01</p> <p>Isotopic analyses of mineral, leachate, and whole rock fractions from the Martian <span class="hlt">shergottite</span> meteorite QUE 94201 yield Rb-Sr and Sm-Nd crystallization ages of 327 +/- 12 and 327 +/- 19 Ma, respectively. These ages are concordant, although the isochrons are defined by different fractions within the meteorite. Comparison of isotope dilution Sm and Nd data for the various QUE 94201 fractions with in situ ion microprobe data for QUE 94201 minerals from the literature demonstrate the presence of a leachable crustal component in the meteorite. This component is likely to have been added to QUE 94201 by secondary alteration processes on Mars, and can affect the isochrons by selectively altering the isotopic systematics of the leachates and some of the mineral fractions. The absence of crustal recycling processes on Mars may preserve the geochemical evidence for early differentiation and the decoupling of the Rb-Sr and Sm-Nd isotopic systems, underscoring one of the fundamental differences between geologic processes on Mars and the Earth.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20070003723','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20070003723"><span id="translatedtitle">Rb-Sr and Sm-Nd Isotopic Studies of Martian Depleted Shergottes SaU 094/005</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Shih, C.-Y.; Nyquist, L. E.; Reese, Y.</p> <p>2007-01-01</p> <p>Sayh <span class="hlt">al</span> Uhaymir (SaU) 094 and SaU 005 are olivine-phyric <span class="hlt">shergottites</span> from the Oman desert and are considered as pairs. [e.g., 1]. They are very similar to the Libyan desert <span class="hlt">shergottite</span> <span class="hlt">Dar</span> <span class="hlt">al</span> Gani (DaG) 476 in petrology, chemistry and ejection age [2-6]. This group of <span class="hlt">shergottites</span>, also recognized as depleted <span class="hlt">shergottites</span> [e.g. 7] has been strongly shocked and contains very low abundances of light rare earth elements (REE). In addition, terrestrial contaminants are commonly present in meteorites found in desert environments. Age-dating these samples is very challenging, but lower calcite contents in the SaU meteorites suggest that they have been subjected to less severe desert weathering than their DaG counterparts [3-4]. In this report, we present Rb-Sr and Sm-Nd isotopic results for SaU 094 and SaU 005, discuss the correlation of their ages with those of other similar <span class="hlt">shergottites</span>, and discuss their petrogenesis.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2016EGUGA..1811609A&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2016EGUGA..1811609A&link_type=ABSTRACT"><span id="translatedtitle">Surface expression of intraplate postglacial faults in Sweden: from Li<span class="hlt">DAR</span> data</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Abduljabbar, Mawaheb; Ask, Maria; Bauer, Tobias; Lund, Björn; Smith, Colby; Mikko, Henrik; Munier, Raymond</p> <p>2016-04-01</p> <p>Large intraplate earthquakes, up to magnitude 8.0±0.3 (Lindblom et <span class="hlt">al</span>. 2015) are inferred to have occurred in northern Fennoscandia at the end of, or just after the Weichselian deglaciation. More than a dozen large so-called postglacial faults (PGF) have been found in the region. The present-day microseismic activity is rather high in north Sweden, and there is a correlation between microseismicity and mapped PGF scarps: 71% of the observed earthquakes north of 66°N locate within 30 km to the southeast and 10 km to the northwest of PGFs (Lindblom et <span class="hlt">al</span>., 2015). Surface expressions of PGFs in Sweden have mainly been mapped using aerial photogrammetry and trenching (e.g. Lagerbäck & Sundh 2008). Their detailed surface geometry may be investigated using the new high-resolution elevation model of Sweden (NNH) that has a vertical- and lateral resolution of 2 m and 0.25 m, respectively. With NNH data, known PGFs have been modified, and a number of new potential PGFs have been identified (Smith et <span class="hlt">al</span>. 2014; Mikko et <span class="hlt">al</span>. 2015). However, the detailed variation of their surface expression remains to be determined. Our main objective is to constrain the strike and surface offset (i.e., apparent vertical throw because of soil cover overlays the bedrock) across the PGF scarps. We anticipate using the results to constrain direction of fault motion and paleomagnitudes of PGFs, and in numerical analyzes to investigate the nature of PGFs. We have developed a methodology for analyzing PGF-geomorphology from Li<span class="hlt">DAR</span> data using two main software platforms (Ask et <span class="hlt">al</span>. 2015): (1) Move2015 by Midland Valley has been used for constructing 3D models of the surface traces of the PGFs to determine apparent vertical throw. The apparent hanging- and footwall cut off lines are digitized, and subsequent computation of coordinates is rather time efficient and provide continuous data of fault and soil geomorphology that can be statistically analyzed; and (2) ArcGIS 10.3 by Esri has mostly been</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2015JPRS..110...66T&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2015JPRS..110...66T&link_type=ABSTRACT"><span id="translatedtitle">Segmenting tree crowns from terrestrial and mobile Li<span class="hlt">DAR</span> data by exploring ecological theories</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Tao, Shengli; Wu, Fangfang; Guo, Qinghua; Wang, Yongcai; Li, Wenkai; Xue, Baolin; Hu, Xueyang; Li, Peng; Tian, Di; Li, Chao; Yao, Hui; Li, Yumei; Xu, Guangcai; Fang, Jingyun</p> <p>2015-12-01</p> <p>The rapid development of light detection and ranging (Li<span class="hlt">DAR</span>) techniques is advancing ecological and forest research. During the last decade, numerous single tree segmentation techniques have been developed using airborne Li<span class="hlt">DAR</span> data. However, accurate crown segmentation using terrestrial or mobile Li<span class="hlt">DAR</span> data, which is an essential prerequisite for extracting branch level forest characteristics, is still challenging mainly because of the difficulties posed by tree crown intersection and irregular crown shape. In the current work, we developed a comparative shortest-path algorithm (CSP) for segmenting tree crowns scanned using terrestrial (T)-Li<span class="hlt">DAR</span> and mobile Li<span class="hlt">DAR</span>. The algorithm consists of two steps, namely trunk detection and subsequent crown segmentation, with the latter inspired by the well-proved metabolic ecology theory and the ecological fact that vascular plants tend to minimize the transferring distance to the root. We tested the algorithm on mobile-Li<span class="hlt">DAR</span>-scanned roadside trees and T-Li<span class="hlt">DAR</span>-scanned broadleaved and coniferous forests in China. Point-level quantitative assessments of the segmentation results showed that for mobile-Li<span class="hlt">DAR</span>-scanned roadside trees, all the points were classified to their corresponding trees correctly, and for T-Li<span class="hlt">DAR</span>-scanned broadleaved and coniferous forests, kappa coefficients ranging from 0.83 to 0.93 were obtained. We believe that our algorithm will make a contribution to solving the problem of crown segmentation in T-Li<span class="hlt">DAR</span> scanned-forests, and might be of interest to researchers in Li<span class="hlt">DAR</span> data processing and to forest ecologists. In addition, our research highlights the advantages of using ecological theories as guidelines for processing Li<span class="hlt">DAR</span> data.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2014ISPAr.XL1...89D&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2014ISPAr.XL1...89D&link_type=ABSTRACT"><span id="translatedtitle">Synergy Between Li<span class="hlt">DAR</span> and Image Data in Context of Building Extraction</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Dal Poz, A. P.</p> <p>2014-11-01</p> <p>This paper compares the paradigms of Li<span class="hlt">DAR</span> and aerophotogrammetry in the context of building extraction and briefly discusses a photogrammetric strategy for refining building roof polyhedrons previously extracted from Li<span class="hlt">DAR</span> data. In general, empirical and theoretical studies have confirmed that Li<span class="hlt">DAR</span>-based methodologies are more suitable in extracting planar roof faces and ridges of the roof, whereas the aerophotogrammetry are more suitable in extracting building roof outlines. In order to exemplify how to explore these properties, it is presented a photogrammetric method for refining 3D building roof contours extracted from airborne Li<span class="hlt">DAR</span> data. Examples of application are provided for this refining approach.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015ArFKT..27...25B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015ArFKT..27...25B"><span id="translatedtitle">Multispectral airborne laser scanning - a new trend in the development of Li<span class="hlt">DAR</span> technology</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Bakuła, K.</p> <p>2015-12-01</p> <p>Airborne laser scanning (<span class="hlt">ALS</span>) is the one of the most accurate remote sensing techniques for data acquisition where the terrain and its coverage is concerned. Modern scanners have been able to scan in two or more channels (frequencies of the laser) recently. This gives the rise to the possibility of obtaining diverse information about an area with the different spectral properties of objects. The paper presents an example of a multispectral <span class="hlt">ALS</span> system - Titan by Optech - with the possibility of data including the analysis of digital elevation models accuracy and data density. As a result of the study, the high relative accuracy of Li<span class="hlt">DAR</span> acquisition in three spectral bands was proven. The mean differences between digital terrain models (DTMs) were less than 0.03 m. The data density analysis showed the influence of the laser wavelength. The points clouds that were tested had average densities of 25, 23 and 20 points per square metre respectively for green (G), near-infrared (NIR) and shortwave-infrared (SWIR) lasers. In this paper, the possibility of the generation of colour composites using orthoimages of laser intensity reflectance and its classification capabilities using data from airborne multispectral laser scanning for land cover mapping are also discussed and compared with conventional photogrammetric techniques.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2009EGUGA..1110967K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2009EGUGA..1110967K"><span id="translatedtitle">Analysis of airborne Li<span class="hlt">DAR</span> as a basis for digital soil mapping in Alpine areas</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kringer, K.; Tusch, M.; Geitner, C.; Meißl, G.; Rutzinger, M.</p> <p>2009-04-01</p> <p>Especially in mountainous regions like the Alps the formation of soil is highly influenced by relief characteristics. Among all factors included in Jenny's (1941) model for soil development, relief is the one most commonly used in approaches to create digital soil maps and to derive soil properties from secondary data sources (McBratney et <span class="hlt">al</span>. 2003). Elevation data, first order (slope, aspect) and second order derivates (plan, profile and cross-sectional curvature) as well as complex morphometric parameters (various landform classifications, e.g., Wood 1996) and compound indices (e.g., topographic wetness indices, vertical distance to drainage network, insolation) can be calculated from digital elevation models (DEM). However, while being an important source of information for digital soil mapping on small map scales, "conventional" DEMs are of limited use for the design of large scale conceptual soil maps for small areas due to rather coarse raster resolutions with cell sizes ranging from 20 to 100 meters. Slight variations in elevation and small landform features might not be discernible even though they might have a significant effect to soil formation, e.g., regarding the influence of groundwater in alluvial soils or the extent of alluvial fans. Nowadays, Airborne Li<span class="hlt">DAR</span> (Light Detection And Ranging) provides highly accurate data for the elaboration of high-resolution digital terrain models (DTM) even in forested areas. In the project LASBO (Laserscanning in der Bodenkartierung) the applicability of digital terrain models derived from Li<span class="hlt">DAR</span> for the identification of soil-relevant geomorphometric parameter is investigated. Various algorithms which were initially designed for coarser raster data are applied on high-resolution DTMs. Test areas for LASBO are located in the region of Bruneck (Italy) and near the municipality of Kramsach in the Inn Valley (Austria). The freely available DTM for Bruneck has a raster resolution of 2.5 meters while in Kramsach a DTM with</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/26712856','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/26712856"><span id="translatedtitle">The Daily Activity Report (<span class="hlt">DAR</span>) a Novel Measure of Functional Outcome for Serious Mental Illness.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Velligan, Dawn I; Mintz, Jim; Sierra, Cynthia; Martin, Mona L; Fredrick, Megan; Maglinte, Gregory A; Corey-Lisle, Patricia K</p> <p>2016-05-01</p> <p>The assessment of real-world functional outcomes in clinical trials for medications targeting negative symptoms and cognitive impairment is extremely important. We tested the psychometric properties of the Daily Activity Report (<span class="hlt">DAR</span>), a novel assessment of productive daily activity. We administered the <span class="hlt">DAR</span> and additional assessments of functional outcome, functional capacity, cognition and symptomatology to 50 individuals with schizophrenia at 2 time points, 1 month apart and to 25 healthy controls. The <span class="hlt">DAR</span> records a person's daily activity for 7 consecutive days based upon phone calls made 3 times a day. A total score and scores in 3 domains; instrumental activities (ie, independent living), social and work or school related activities are generated for the <span class="hlt">DAR</span>. Inter-item consistency was high 0.89-0.94 for each domain and 0.88 overall. Test-retest reliability across 1 month for the total <span class="hlt">DAR</span> score was 0.67,P< .0001. The total <span class="hlt">DAR</span> score as well as scores for social activity and nondomestic work/school differed significantly between control and patient participants (P< .0001). <span class="hlt">DAR</span> domain scores were associated with negative symptoms and functional outcomes, but the primary score related to these measures was the work/school dimension of the <span class="hlt">DAR</span>. <span class="hlt">DAR</span> scores were only weakly and nonsignificantly related to positive symptoms. This study provides preliminary support for the reliability and validity of the <span class="hlt">DAR</span> using interviewer administration. The development of a patient reported version of the <span class="hlt">DAR</span> using smart phone technology with automatic scoring is the next step. PMID:26712856</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4838101','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4838101"><span id="translatedtitle">The Daily Activity Report (<span class="hlt">DAR</span>) a Novel Measure of Functional Outcome for Serious Mental Illness</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Velligan, Dawn I.; Mintz, Jim; Sierra, Cynthia; Martin, Mona L.; Fredrick, Megan; Maglinte, Gregory A.; Corey-Lisle, Patricia K.</p> <p>2016-01-01</p> <p>The assessment of real-world functional outcomes in clinical trials for medications targeting negative symptoms and cognitive impairment is extremely important. We tested the psychometric properties of the Daily Activity Report (<span class="hlt">DAR</span>), a novel assessment of productive daily activity. We administered the <span class="hlt">DAR</span> and additional assessments of functional outcome, functional capacity, cognition and symptomatology to 50 individuals with schizophrenia at 2 time points, 1 month apart and to 25 healthy controls. The <span class="hlt">DAR</span> records a person’s daily activity for 7 consecutive days based upon phone calls made 3 times a day. A total score and scores in 3 domains; instrumental activities (ie, independent living), social and work or school related activities are generated for the <span class="hlt">DAR</span>. Inter-item consistency was high 0.89–0.94 for each domain and 0.88 overall. Test–retest reliability across 1 month for the total <span class="hlt">DAR</span> score was 0.67, P < .0001. The total <span class="hlt">DAR</span> score as well as scores for social activity and nondomestic work/school differed significantly between control and patient participants (P < .0001). <span class="hlt">DAR</span> domain scores were associated with negative symptoms and functional outcomes, but the primary score related to these measures was the work/school dimension of the <span class="hlt">DAR</span>. <span class="hlt">DAR</span> scores were only weakly and nonsignificantly related to positive symptoms. This study provides preliminary support for the reliability and validity of the <span class="hlt">DAR</span> using interviewer administration. The development of a patient reported version of the <span class="hlt">DAR</span> using smart phone technology with automatic scoring is the next step. PMID:26712856</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3694930','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3694930"><span id="translatedtitle">Genetic Diversity and Population Structure of Tetraploid Wheats (Triticum turgidum L.) Estimated by SSR, <span class="hlt">DAr</span>T and Pedigree Data</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Laidò, Giovanni; Mangini, Giacomo; Taranto, Francesca; Gadaleta, Agata; Blanco, Antonio; Cattivelli, Luigi; Marone, Daniela; Mastrangelo, Anna M.; Papa, Roberto; De Vita, Pasquale</p> <p>2013-01-01</p> <p>Levels of genetic diversity and population genetic structure of a collection of 230 accessions of seven tetraploid Triticum turgidum L. subspecies were investigated using six morphological, nine seed storage protein loci, 26 SSRs and 970 <span class="hlt">DAr</span>T markers. The genetic diversity of the morphological traits and seed storage proteins was always lower in the durum wheat compared to the wild and domesticated emmer. Using Bayesian clustering (K = 2), both of the sets of molecular markers distinguished the durum wheat cultivars from the other tetraploid subspecies, and two distinct subgroups were detected within the durum wheat subspecies, which is in agreement with their origin and year of release. The genetic diversity of morphological traits and seed storage proteins was always lower in the improved durum cultivars registered after 1990, than in the intermediate and older ones. This marked effect on diversity was not observed for molecular markers, where there was only a weak reduction. At K >2, the SSR markers showed a greater degree of resolution than for <span class="hlt">DAr</span>T, with their identification of a greater number of groups within each subspecies. Analysis of <span class="hlt">DAr</span>T marker differentiation between the wheat subspecies indicated outlier loci that are potentially linked to genes controlling some important agronomic traits. Among the 211 loci identified under selection, 109 markers were recently mapped, and some of these markers were clustered into specific regions on chromosome arms 2BL, 3BS and 4<span class="hlt">AL</span>, where several genes/quantitative trait loci (QTLs) are involved in the domestication of tetraploid wheats, such as the tenacious glumes (Tg) and brittle rachis (Br) characteristics. On the basis of these results, it can be assumed that the population structure of the tetraploid wheat collection partially reflects the evolutionary history of Triticum turgidum L. subspecies and the genetic potential of landraces and wild accessions for the detection of unexplored alleles. PMID:23826256</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013CG.....54..122V','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013CG.....54..122V"><span id="translatedtitle">Performance testing of Li<span class="hlt">DAR</span> exploitation software</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Varela-González, M.; González-Jorge, H.; Riveiro, B.; Arias, P.</p> <p>2013-04-01</p> <p>Mobile Li<span class="hlt">DAR</span> systems are being used widely in recent years for many applications in the field of geoscience. One of most important limitations of this technology is the large computational requirements involved in data processing. Several software solutions for data processing are available in the market, but users are often unknown about the methodologies to verify their performance accurately. In this work a methodology for Li<span class="hlt">DAR</span> software performance testing is presented and six different suites are studied: QT Modeler, AutoCAD Civil 3D, Mars 7, Fledermaus, Carlson and TopoDOT (all of them in x64). Results depict as QTModeler, TopoDOT and AutoCAD Civil 3D allow the loading of large datasets, while Fledermaus, Mars7 and Carlson do not achieve these powerful performance. AutoCAD Civil 3D needs large loading time in comparison with the most powerful softwares such as QTModeler and TopoDOT. Carlson suite depicts the poorest results among all the softwares under study, where point clouds larger than 5 million points cannot be loaded and loading time is very large in comparison with the other suites even for the smaller datasets. AutoCAD Civil 3D, Carlson and TopoDOT show more threads than other softwares like QTModeler, Mars7 and Fledermaus.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2015AGUFMNH41B1805K&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2015AGUFMNH41B1805K&link_type=ABSTRACT"><span id="translatedtitle">Identifying Colluvial Slopes by Airborne Li<span class="hlt">DAR</span> Analysis</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kasai, M.; Marutani, T.; Yoshida, H.</p> <p>2015-12-01</p> <p>Colluvial slopes are one of major sources of landslides. Identifying the locations of the slopes will help reduce the risk of disasters, by avoiding building infrastructure and properties nearby, or if they are already there, by applying appropriate counter measures before it suddenly moves. In this study, airborne Li<span class="hlt">DAR</span> data was analyzed to find their geomorphic characteristics to use for extracting their locations. The study site was set in the suburb of Sapporo City, Hokkaido in Japan. The area is underlain by Andesite and Tuff and prone to landslides. Slope angle and surface roughness were calculated from 5 m resolution DEM. These filters were chosen because colluvial materials deposit at around the angle of repose and accumulation of loose materials was considered to form a peculiar surface texture differentiable from other slope types. Field survey conducted together suggested that colluvial slopes could be identified by the filters with a probability of 80 percent. Repeat Li<span class="hlt">DAR</span> monitoring of the site by an unmanned helicopter indicated that those slopes detected as colluviums appeared to be moving at a slow rate. In comparison with a similar study from the crushed zone in Japan, the range of slope angle indicative of colluviums agreed with the Sapporo site, while the texture was rougher due to larger debris composing the slopes.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013M%26PS...48.1359B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013M%26PS...48.1359B"><span id="translatedtitle">Magmatic history and parental melt composition of olivine-phyric <span class="hlt">shergottite</span> LAR 06319: Importance of magmatic degassing and olivine antecrysts in Martian magmatism</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Balta, J. Brian; Sanborn, Matthew; McSween, Harry Y.; Wadhwa, Meenakshi</p> <p>2013-08-01</p> <p>Several olivine-phyric <span class="hlt">shergottites</span> contain enough olivine that they could conceivably represent the products of closed-system crystallization of primary melts derived from partial melting of the Martian mantle. Larkman Nunatak (LAR) 06319 has been suggested to represent a close approach to a Martian primary liquid composition based on approximate equilibrium between its olivine and groundmass. To better understand the olivine-melt relationship and the evolution of this meteorite, we report the results of new petrographic and chemical analyses. We find that olivine megacryst cores are generally not in equilibrium with the groundmass, but rather have been homogenized by diffusion to Mg# 72. We have identified two unique grain types: an olivine glomerocryst and an olivine grain preserving a primary magmatic boundary that constrains the time scale of eruption to be on the order of hours. We also report the presence of trace oxide phases and phosphate compositions that suggest that the melt contained approximately 1.1% H2O and lost volatiles during cooling, also associated with an increase in oxygen fugacity upon degassing. We additionally report in situ rare earth element measurements of the various mineral phases in LAR 06319. Based on these reported trace element abundances, we estimate the oxygen fugacity in the LAR 06319 parent melt early in its crystallization sequence (i.e., at the time of crystallization of the low-Ca and high-Ca pyroxenes), the rare earth element composition of the parent melt, and those of melts in equilibrium with later formed phases. We suggest that LAR 06319 represents the product of closed-system crystallization within a shallow magma chamber, with additional olivine accumulated from a cumulate pile. We infer that the olivine megacrysts are antecrysts, derived from a single magma chamber, but not directly related to the host magma, and suggest that mixing of antecrysts within magma chambers may be a common process in Martian magmatic</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://pubs.er.usgs.gov/publication/70140317','USGSPUBS'); return false;" href="http://pubs.er.usgs.gov/publication/70140317"><span id="translatedtitle">Remote sensing of Sonoran Desert vegetation structure and phenology with ground-based Li<span class="hlt">DAR</span></span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Sankey, Joel B.; Munson, Seth M.; Webb, Robert H.; Wallace, Cynthia S.A.; Duran, Cesar M.</p> <p>2015-01-01</p> <p>Long-term vegetation monitoring efforts have become increasingly important for understanding ecosystem response to global change. Many traditional methods for monitoring can be infrequent and limited in scope. Ground-based Li<span class="hlt">DAR</span> is one remote sensing method that offers a clear advancement to monitor vegetation dynamics at high spatial and temporal resolution. We determined the effectiveness of Li<span class="hlt">DAR</span> to detect intra-annual variability in vegetation structure at a long-term Sonoran Desert monitoring plot dominated by cacti, deciduous and evergreen shrubs. Monthly repeat Li<span class="hlt">DAR</span> scans of perennial plant canopies over the course of one year had high precision. Li<span class="hlt">DAR</span> measurements of canopy height and area were accurate with respect to total station survey measurements of individual plants. We found an increase in the number of Li<span class="hlt">DAR</span> vegetation returns following the wet North American Monsoon season. This intra-annual variability in vegetation structure detected by Li<span class="hlt">DAR</span> was attributable to a drought deciduous shrub Ambrosia deltoidea, whereas the evergreen shrub Larrea tridentata and cactus Opuntia engelmannii had low variability. Benefits of using Li<span class="hlt">DAR</span> over traditional methods to census desert plants are more rapid, consistent, and cost-effective data acquisition in a high-resolution, 3-dimensional context. We conclude that repeat Li<span class="hlt">DAR</span> measurements can be an effective method for documenting ecosystem response to desert climatology and drought over short time intervals and at detailed-local spatial scale.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013AGUSM.G31A..02L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013AGUSM.G31A..02L"><span id="translatedtitle">Li<span class="hlt">DAR</span>, a great tool for archaeologists, but how do you interpret it?</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Leisz, S.; Fisher, C.</p> <p>2013-05-01</p> <p>This paper focuses on the use of airborne Li<span class="hlt">DAR</span> to identify archaeological features below forest canopies in Mesoamerica and the challenges faced in interpreting the data. To illustrate the issues involved in interpreting Li<span class="hlt">DAR</span> point clouds and derived data sets for archaeological purposes, the case study of the use of airborne Li<span class="hlt">DAR</span> at the archaeological site of Angamuco in West-Central Mexico is discussed. The case study details the reason Li<span class="hlt">DAR</span> was collected, the challenges in interpreting it, methods and techniques that the authors are investigating to improve the interpretation of the Li<span class="hlt">DAR</span>, and discoveries that have so far been made through the use of Li<span class="hlt">DAR</span>. A key point discussed is the need to analyze the Li<span class="hlt">DAR</span> point cloud in conjunction with products developed from the point cloud. Analyzing the various data sets jointly allows the user to better identify archaeological features of interest. New ways of utilizing hillshades of DEMs, such as creating 360 degree hillshades of the derived DEMs, are also presented. Last the authors discuss their experience in using object-based classification of the products derived from the Li<span class="hlt">DAR</span> point cloud as an example of one possible technique for automating the delineation and classification of archaeological features.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://files.eric.ed.gov/fulltext/ED091086.pdf','ERIC'); return false;" href="http://files.eric.ed.gov/fulltext/ED091086.pdf"><span id="translatedtitle">Dia de <span class="hlt">Dar</span> Gracias. Modulo Nivel Primario. (Day to Give Thanks. Module Primary Level.)</span></a></p> <p><a target="_blank" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>Espinoza, Delia; Lopez, Santiago, III</p> <p></p> <p>Dia de <span class="hlt">Dar</span> Gracias (Thanksgiving) is the subject of this primary level unit. The unit objectives are to: (1) know about El Dia de <span class="hlt">Dar</span> Gracias as it is celebrated in the United States; (2) know how the Mayas celebrated it; (3) understand the context of the stories in the unit; (4) know about the main food used, the turkey; (5) distinguish other…</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013AGUFM.G22A..03M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013AGUFM.G22A..03M"><span id="translatedtitle">4D Terrestrial Li<span class="hlt">DAR</span> Data Collection: Geomorphic and Hydraulic Applications (Invited)</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Minear, J. T.; Wright, S. A.; Kinzel, P. J.; Draut, A. E.; Logan, J.</p> <p>2013-12-01</p> <p>Terrestrial Li<span class="hlt">DAR</span>, also known as T-Li<span class="hlt">DAR</span>, ground-based Li<span class="hlt">DAR</span>, or Terrestrial Laser Scanning, can provide great insights into some types of geomorphic and hydraulic studies, particularly when collected repeatedly over time. Because T-Li<span class="hlt">DAR</span> collects a large amount of data on a set grid, oftentimes processes are inadvertently captured that are not part of the initial research question but can be important factors in their own right. In addition, though T-Li<span class="hlt">DAR</span> is most often used at relatively small sites for high-precision scanning, it also can be used for relatively rapid meso-scale site measurements, albeit typically with less precision. Using examples from the Elwha River dam removals, WA, a canal experiment in NE, and several small river restoration sites in CA, we highlight several important and innovative uses of T-Li<span class="hlt">DAR</span> measurements, including quick temporal scale changes in water surface features and larger temporal- and spatial-scale changes in reservoir deltaic deposits and longitudinal profile features. Also discussed will be some considerations for improving T-Li<span class="hlt">DAR</span> error estimation and a comparison to other data collection techniques, including aerial Li<span class="hlt">DAR</span>, structure-from-motion photogrammetry, and UAV- and plane-captured photogrammetry.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ars.usda.gov/research/publications/Publications.htm?seq_no_115=299186','TEKTRAN'); return false;" href="http://www.ars.usda.gov/research/publications/Publications.htm?seq_no_115=299186"><span id="translatedtitle">Wetland inundation mapping and change monitoring using landsat and airborne Li<span class="hlt">DAR</span> data</span></a></p> <p><a target="_blank" href="http://www.ars.usda.gov/services/TekTran.htm">Technology Transfer Automated Retrieval System (TEKTRAN)</a></p> <p></p> <p></p> <p>This paper presents a new approach for mapping wetland inundation change using Landsat and Li<span class="hlt">DAR</span> intensity data. In this approach, Li<span class="hlt">DAR</span> data were used to derive highly accurate reference subpixel inundation percentage (SIP) maps at the 30-m resolution. The reference SIP maps were then used to est...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2012EGUGA..1413168F&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2012EGUGA..1413168F&link_type=ABSTRACT"><span id="translatedtitle">2011 Japan tsunami survivor video based hydrograph and flow velocity measurements using Li<span class="hlt">DAR</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Fritz, H. M.; Phillips, D. A.; Okayasu, A.; Shimozono, T.; Liu, H.; Mohammed, F.; Skanavis, V.; Synolakis, C. E.; Takahashi, T.</p> <p>2012-04-01</p> <p>On March 11, 2011, a magnitude Mw 9.0 earthquake occurred off the coast of Japan's Tohoku region causing catastrophic damage and loss of life. Numerous tsunami reconnaissance trips were conducted in Japan (Tohoku Earthquake and Tsunami Joint Survey Group). This report focuses on the surveys at 9 tsunami eyewitness video recording locations in Yoriisohama, Kesennuma, Kamaishi and Miyako along Japan's Sanriku coast and the subsequent video image calibration, processing, tsunami hydrograph and flow velocity analysis. Selected tsunami video recording sites were visited, eyewitnesses interviewed and some ground control points recorded during the initial tsunami reconnaissance from April 9 to 25. A follow-up survey from June 9 to 15, 2011 focused on terrestrial laser scanning (TLS) at locations with previously identified high quality eyewitness videos. We acquired precise topographic data using TLS at nine video sites with multiple scans acquired from different instrument positions at each site. These ground-based Li<span class="hlt">DAR</span> measurements produce a 3-dimensional "point cloud" dataset. Digital photography from a scanner-mounted camera yields photorealistic 3D images. Integrated GPS measurements allow accurate georeferencing of the TLS data in an absolute reference frame such as WGS84. We deployed a Riegl VZ-400 scanner (1550 nm wavelength laser, 42,000 measurements/second, <600 meter max range) and peripheral equipment from the UNAVCO instrument pool. The original full length videos recordings were recovered from eyewitnesses and the Japanese Coast Guard (JCG). Multiple videos were synchronized and referenced in time (UTC). The analysis of the tsunami videos follows a four step procedure developed for the analysis of 2004 Indian Ocean tsunami videos at Banda Aceh, Indonesia (Fritz et <span class="hlt">al</span>., 2006). The first step requires the calibration of the sector of view present in the eyewitness video recording based on visually identifiable ground control points measured in the Li<span class="hlt">DAR</span> point</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2011AGUFMNH13G..05F&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2011AGUFMNH13G..05F&link_type=ABSTRACT"><span id="translatedtitle">2011 Japan tsunami current and flow velocity measurements from survivor videos using Li<span class="hlt">DAR</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Fritz, H. M.; Phillips, D. A.; Okayasu, A.; Shimozono, T.; Liu, H.; Mohammed, F.; Skanavis, V.; Synolakis, C.; Takahashi, T.</p> <p>2011-12-01</p> <p>On March 11, 2011, a magnitude Mw 9.0 earthquake occurred off the coast of Japan's Tohoku region causing catastrophic damage and loss of life. Numerous tsunami reconnaissance trips were conducted in Japan (Tohoku Earthquake and Tsunami Joint Survey Group). This report focuses on the surveys at 9 tsunami eyewitness video recording locations in Yoriisohama, Kesennuma, Kamaishi and Miyako along Japan's Sanriku coast and the subsequent video image calibration, processing and tsunami flow velocity analysis. Selected tsunami video recording sites were visited, eyewitnesses interviewed and some ground control points recorded during the initial tsunami reconnaissance from April 9 to 25. A follow-up survey from June 9 to 15, 2011 focused on terrestrial laser scanning (TLS) at locations with previously identified high quality eyewitness videos. We acquired precise topographic data using TLS at nine video sites with multiple scans acquired from different instrument positions at each site. These ground-based Li<span class="hlt">DAR</span> measurements produce a 3-dimensional "point cloud" dataset. Digital photography from a scanner-mounted camera yields photorealistic 3D images. Integrated GPS measurements allow accurate georeferencing of the TLS data in an absolute reference frame such as WGS84. We deployed a Riegl VZ-400 scanner (1550 nm wavelength laser, 42,000 measurements/second, <600 meter max range) and peripheral equipment from the UNAVCO instrument pool. The original full length videos recordings were recovered from eyewitnesses and the Japanese Coast Guard (JCG). Multiple videos were synchronized and referenced in time (UTC). The analysis of the tsunami videos follows a four step procedure developed for the analysis of 2004 Indian Ocean tsunami videos at Banda Aceh, Indonesia (Fritz et <span class="hlt">al</span>., 2006). The first step requires the calibration of the sector of view present in the eyewitness video recording based on visually identifiable ground control points measured in the Li<span class="hlt">DAR</span> point cloud data</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_8");'>8</a></li> <li><a href="#" onclick='return showDiv("page_9");'>9</a></li> <li class="active"><span>10</span></li> <li><a href="#" onclick='return showDiv("page_11");'>11</a></li> <li><a href="#" onclick='return showDiv("page_12");'>12</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_10 --> <div id="page_11" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_9");'>9</a></li> <li><a href="#" onclick='return showDiv("page_10");'>10</a></li> <li class="active"><span>11</span></li> <li><a href="#" onclick='return showDiv("page_12");'>12</a></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="201"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012AdG....32...31H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012AdG....32...31H"><span id="translatedtitle">Snow accumulation of a high alpine catchment derived from Li<span class="hlt">DAR</span> measurements</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Helfricht, K.; Schöber, J.; Seiser, B.; Fischer, A.; Stötter, J.; Kuhn, M.</p> <p>2012-12-01</p> <p>The spatial distribution of snow accumulation substantially affects the seasonal course of water storage and runoff generation in high mountain catchments. Whereas the areal extent of snow cover can be recorded by satellite data, spatial distribution of snow depth and hence snow water equivalent (SWE) is difficult to measure on catchment scale. In this study we present the application of airborne Li<span class="hlt">DAR</span> (Light Detecting And Ranging) data to extract snow depths and accumulation distribution in an alpine catchment. Airborne Li<span class="hlt">DAR</span> measurements were performed in a glacierized catchment in the Ötztal Alps at the beginning and the end of three accumulation seasons. The resulting digital elevation models (DEMs) were used to calculate surface elevation changes throughout the winter season. These surface elevation changes were primarily referred to as snow depths and are discussed concerning measured precipitation and the spatial characteristics of the accumulation distribution in glacierized and unglacierized areas. To determine the redistribution of catchment precipitation, snow depths were converted into SWE using a simple regression model. Snow accumulation gradients and snow redistribution were evaluated for 100 m elevation bands. Mean surface elevation changes of the whole catchment ranges from 1.97 m to 2.65 m within the analyzed accumulation seasons. By analyzing the distribution of the snow depths, elevation dependent patterns were obtained as a function of the topography in terms of aspect and slope. The high resolution DEMs show clearly the higher variation of snow depths in rough unglacierized areas compared to snow depths on smooth glacier surfaces. Mean snow depths in glacierized areas are higher than in unglacierized areas. Maximum mean snow depths of 100 m elevation bands are found between 2900 m and 3000 m a.s.l. in unglacierized areas and between 2800 m and 2900 m a.s.l. in glacierized areas, respectively. Calculated accumulation gradients range from 8% to</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013AGUFMEP43C0871C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013AGUFMEP43C0871C"><span id="translatedtitle">Applicability of Aerial Green Li<span class="hlt">DAR</span> to a Large River in the Western United States</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Conner, J. T.; Welcker, C. W.; Cooper, C.; Faux, R.; Butler, M.; Nayegandhi, A.</p> <p>2013-12-01</p> <p>In October 2012, aerial green Li<span class="hlt">DAR</span> data were collected in the Snake River (within Idaho and Oregon) to test this emerging technology in a large river with poor water clarity. Six study areas (total of 30 river miles spread out over 250 river miles) were chosen to represent a variety of depths, channel types, and surface conditions to test the accuracy, depth penetration, data density of aerial green Li<span class="hlt">DAR</span>. These characteristics along with cost and speed of acquisition were compared to other bathymetric survey techniques including rod surveys (total station and RTK-GPS), single-beam sonar, and multibeam echosounder (MBES). The green Li<span class="hlt">DAR</span> system typically measured returns from the riverbed through 1-2 meters of water, which was less than one Secchi depth. However, in areas with steep banks or aquatic macrophytes, Li<span class="hlt">DAR</span> returns from the riverbed were less frequent or non-existent. In areas of good return density, depths measured from green Li<span class="hlt">DAR</span> data corresponded well with previously collected data sets from traditional bathymetric survey techniques. In such areas, the green Li<span class="hlt">DAR</span> point density was much higher than both rod and single beam sonar surveys, yet lower than MBES. The green Li<span class="hlt">DAR</span> survey was also collected more efficiently than all other methods. In the Snake River, green Li<span class="hlt">DAR</span> does not provide a method to map the entire riverbed as it only receives bottom returns in shallow water, typically at the channel margins. However, green Li<span class="hlt">DAR</span> does provide survey data that is an excellent complement to MBES, which is more effective at surveying the deeper portions of the channel. In some cases, the green Li<span class="hlt">DAR</span> was able to provide data in areas that the MBES could not, often due to issues with navigating the survey boat in shallow water. Even where both MBES and green Li<span class="hlt">DAR</span> mapped the river bottom, green Li<span class="hlt">DAR</span> often provides more accurate data through a better angle of incidence and less shadowing than the MBES survey. For one MBES survey in 2013, the green Li<span class="hlt">DAR</span></p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/23202177','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/23202177"><span id="translatedtitle">Multipath estimation in urban environments from joint GNSS receivers and Li<span class="hlt">DAR</span> sensors.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Ali, Khurram; Chen, Xin; Dovis, Fabio; De Castro, David; Fernández, Antonio J</p> <p>2012-01-01</p> <p>In this paper, multipath error on Global Navigation Satellite System (GNSS) signals in urban environments is characterized with the help of Light Detection and Ranging (Li<span class="hlt">DAR</span>) measurements. For this purpose, Li<span class="hlt">DAR</span> equipment and Global Positioning System (GPS) receiver implementing a multipath estimating architecture were used to collect data in an urban environment. This paper demonstrates how GPS and Li<span class="hlt">DAR</span> measurements can be jointly used to model the environment and obtain robust receivers. Multipath amplitude and delay are estimated by means of Li<span class="hlt">DAR</span> feature extraction and multipath mitigation architecture. The results show the feasibility of integrating the information provided by Li<span class="hlt">DAR</span> sensors and GNSS receivers for multipath mitigation. PMID:23202177</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/26560612','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/26560612"><span id="translatedtitle">Using a multiwavelength Li<span class="hlt">DAR</span> for improved remote sensing of natural waters.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Gray, Deric J; Anderson, John; Nelson, Jean; Edwards, Jarrod</p> <p>2015-11-01</p> <p>This paper describes research to characterize the benefits of a multiwavelength oceanographic Li<span class="hlt">DAR</span> for various water types. Field measurements were conducted to establish endmembers representative of both typical and extremely challenging natural conditions. Laboratory tests were performed using a prototype multiwavelength Li<span class="hlt">DAR</span> in water tanks with optical conditions simulating both sediment-laden and biologically rich water types. Li<span class="hlt">DAR</span> models were used to simulate the Li<span class="hlt">DAR</span> signal from both field and laboratory experiments. Our measurements and models show that using a laser wavelength of 470-490 nm in the open ocean leads to an improvement factor of 1.50-1.75 compared to a 532 nm system. In more turbid areas using a laser wavelength of 560-580 nm leads to an improvement factor of 1.25. We conclude by demonstrating how using multiple Li<span class="hlt">DAR</span> wavelengths can help detect and characterize constituents in the water column. PMID:26560612</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3522930','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3522930"><span id="translatedtitle">Multipath Estimation in Urban Environments from Joint GNSS Receivers and Li<span class="hlt">DAR</span> Sensors</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Ali, Khurram; Chen, Xin; Dovis, Fabio; De Castro, David; Fernández, Antonio J.</p> <p>2012-01-01</p> <p>In this paper, multipath error on Global Navigation Satellite System (GNSS) signals in urban environments is characterized with the help of Light Detection and Ranging (Li<span class="hlt">DAR</span>) measurements. For this purpose, Li<span class="hlt">DAR</span> equipment and Global Positioning System (GPS) receiver implementing a multipath estimating architecture were used to collect data in an urban environment. This paper demonstrates how GPS and Li<span class="hlt">DAR</span> measurements can be jointly used to model the environment and obtain robust receivers. Multipath amplitude and delay are estimated by means of Li<span class="hlt">DAR</span> feature extraction and multipath mitigation architecture. The results show the feasibility of integrating the information provided by Li<span class="hlt">DAR</span> sensors and GNSS receivers for multipath mitigation. PMID:23202177</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20100008620','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20100008620"><span id="translatedtitle">SM-ND Age and REE Systematics of Larkman Nunatek 06319: Closed System Fractional Crystallization of a <span class="hlt">Shergottite</span> Magma</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Shafer, J. T.; Brandon, A. D.; Lapen T. J.; Righter, M.; Peslier, A. H.</p> <p>2010-01-01</p> <p>Sm-Nd isotopic data were collected on mineral separates and bulk rock powders of LAR 06319, yielding an age of 180+/-13 Ma (2(sigma)). This age is concordant with the Lu-Hf age (197+/-29 Ma, [1]) determined in conjunction with these data and the Sm-Nd age (190+/-26 Ma) of Shih et <span class="hlt">al</span>., 2009 [2]. The Sm-Nd data form at statistically significant isochron (Fig. 1) that is controlled largely by leachate-residue pairs (samples with the R suffix are residues after leaching in cold 2N HCl for 10 minutes).</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013EGUGA..1512078G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013EGUGA..1512078G"><span id="translatedtitle">A comparison of the accuracy of pixel based and object based classifications of integrated optical and Li<span class="hlt">DAR</span> data</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Gajda, Agnieszka; Wójtowicz-Nowakowska, Anna</p> <p>2013-04-01</p> <p>A comparison of the accuracy of pixel based and object based classifications of integrated optical and Li<span class="hlt">DAR</span> data Land cover maps are generally produced on the basis of high resolution imagery. Recently, Li<span class="hlt">DAR</span> (Light Detection and Ranging) data have been brought into use in diverse applications including land cover mapping. In this study we attempted to assess the accuracy of land cover classification using both high resolution aerial imagery and Li<span class="hlt">DAR</span> data (airborne laser scanning, <span class="hlt">ALS</span>), testing two classification approaches: a pixel-based classification and object-oriented image analysis (OBIA). The study was conducted on three test areas (3 km2 each) in the administrative area of Kraków, Poland, along the course of the Vistula River. They represent three different dominating land cover types of the Vistula River valley. Test site 1 had a semi-natural vegetation, with riparian forests and shrubs, test site 2 represented a densely built-up area, and test site 3 was an industrial site. Point clouds from <span class="hlt">ALS</span> and ortophotomaps were both captured in November 2007. Point cloud density was on average 16 pt/m2 and it contained additional information about intensity and encoded RGB values. Ortophotomaps had a spatial resolution of 10 cm. From point clouds two raster maps were generated: intensity (1) and (2) normalised Digital Surface Model (nDSM), both with the spatial resolution of 50 cm. To classify the aerial data, a supervised classification approach was selected. Pixel based classification was carried out in ERDAS Imagine software. Ortophotomaps and intensity and nDSM rasters were used in classification. 15 homogenous training areas representing each cover class were chosen. Classified pixels were clumped to avoid salt and pepper effect. Object oriented image object classification was carried out in eCognition software, which implements both the optical and <span class="hlt">ALS</span> data. Elevation layers (intensity, firs/last reflection, etc.) were used at segmentation stage due to</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=20020045649&hterms=learn&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3Dlearn','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=20020045649&hterms=learn&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3Dlearn"><span id="translatedtitle"><span class="hlt">Dar</span> <span class="hlt">Al</span> Gani 872: Yet Another Eucrite, Yet Another Lesson to Learn?</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Patzer, A.; Hill, D. H.; Boynton, W. V.; Sipiera, P. P.; Jerman, G. A.</p> <p>2002-01-01</p> <p>We present chemical and mineralogical data on a new monomict basaltic eucrite recovered from Libya. In contrast to most other eucrites, it exhibits high shock features, unusually heterogeneous exsolution of pigeonite, and interesting melt pockets. Additional information is contained in the original extended abstract.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015EGUGA..1714770R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015EGUGA..1714770R"><span id="translatedtitle">Dynamic Li<span class="hlt">DAR</span>-NDVI classification of fluvial landscape units</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Ramírez-Núñez, Carolina; Parrot, Jean-François</p> <p>2015-04-01</p> <p>The lower basin of the Coatzacoalcos River is a wide floodplain in which, during the wet season, local and major flooding are distinguished. Both types of floods, intermittent and regional, are important in terms of resources; the regional flood sediments enrich the soils of the plains and intermittent floods allow obtaining aquatic resources for subsistence during the heatwave. In the floodplain different abandoned meanders and intermittent streams are quickly colonized by aquatic vegetation. However, from the 1990s, the Coatzacoalcos River floodplain has important topographic changes due to mining, road and bridges construction; erosion and sedimentation requires continuous parcel boundaries along with the increasing demand of channel reparation, embankments, levees and bridges associated to tributaries. NDVI data, Li<span class="hlt">DAR</span> point cloud and various types of flood simulations taking into account the DTM are used to classify the dynamic landscape units. These units are associated to floods in relation with water resources, agriculture and livestock. In the study area, the first returns of the point cloud allow extracting vegetation strata. The last returns correspond to the bare earth surface, especially in this area with few human settlements. The surface that is not covered by trees or by aquatic vegetation, correspond to crops, pastures and bare soils. The classification is obtained by using the NDVI index coupled with vegetation strata and water bodies. The result shows that 47.96% of the area does not present active vegetation and it includes 31.53% of bare soils. Concerning the active vegetation, pastures, bushes and trees represent respectively 25.59%, 11.14% and 13.25%. The remaining 1.25% is distributed between water bodies with aquatic vegetation, trees and shrubs. Dynamic landscape units' classification represents a tool for monitoring water resources in a fluvial plain. This approach can be also applied to forest management, environmental services and</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/19440962','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/19440962"><span id="translatedtitle">Urban agriculture and Anopheles habitats in <span class="hlt">Dar</span> es Salaam, Tanzania.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Dongus, Stefan; Nyika, Dickson; Kannady, Khadija; Mtasiwa, Deo; Mshinda, Hassan; Gosoniu, Laura; Drescher, Axel W; Fillinger, Ulrike; Tanner, Marcel; Killeen, Gerry F; Castro, Marcia C</p> <p>2009-05-01</p> <p>A cross-sectional survey of agricultural areas, combined with routinely monitored mosquito larval information, was conducted in urban <span class="hlt">Dar</span> es Salaam, Tanzania, to investigate how agricultural and geographical features may influence the presence of Anopheles larvae. Data were integrated into a geographical information systems framework, and predictors of the presence of Anopheles larvae in farming areas were assessed using multivariate logistic regression with independent random effects. It was found that more than 5% of the study area (total size 16.8 km2) was used for farming in backyard gardens and larger open spaces. The proportion of habitats containing Anopheles larvae was 1.7 times higher in agricultural areas compared to other areas (95% confidence interval = 1.56-1.92). Significant geographic predictors of the presence of Anopheles larvae in gardens included location in lowland areas, proximity to river, and relatively impermeable soils. Agriculture-related predictors comprised specific seedbed types, mid-sized gardens, irrigation by wells, as well as cultivation of sugar cane or leafy vegetables. Negative predictors included small garden size, irrigation by tap water, rainfed production and cultivation of leguminous crops or fruit trees. Although there was an increased chance of finding Anopheles larvae in agricultural sites, it was found that breeding sites originated by urban agriculture account for less than a fifth of all breeding sites of malaria vectors in <span class="hlt">Dar</span> es Salaam. It is suggested that strategies comprising an integrated malaria control effort in malaria-endemic African cities include participatory involvement of farmers by planting shade trees near larval habitats. PMID:19440962</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2004AcAau..54..503B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2004AcAau..54..503B"><span id="translatedtitle">S-<span class="hlt">DARS</span> broadcast from inclined, elliptical orbits</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Briskman, Robert D.; Prevaux, Robert J.</p> <p>2004-04-01</p> <p>The first Sirius spacecraft was launched on July 1, 2000. Exactly 5 months later, on December 1, the third spacecraft was launched, completing the three satellite S-<span class="hlt">DARS</span> (Satellite Digital Audio Radio Service) constellation. The three satellites are deployed in inclined, elliptical, geosynchronous orbits, which allow seamless broadcast coverage to mobile users in the contiguous US. Terrestrial broadcast repeaters provide service in urban cores. The system is in operation, providing the first ever S-<span class="hlt">DARS</span> service. The constellation design results in satellite ground tracks over North America with two satellites always above the equator. High elevation look angles from the mobile ground terminals to the satellites minimize performance degradation due to blockage, foliage attenuation and multi-path. The spacecraft were built by Space Systems/Loral using the 1300 bus modified for operation in high inclination orbits. Each spacecraft was launched using a dedicated Russian Proton booster. The satellite payload is a bent pipe repeater using 7.1 GHz for the uplink and 2.3 GHz for the broadcast transmission. The repeater high-power amplification stage consists of 32 Traveling Wave Tube Amplifiers phase combined to yield a total radio frequency output power of nearly 4 kW at saturated operation. The satellite antennas are mechanically steered to maintain the transmit beam centered on the Contiguous United States and the receive beam centered on the uplink earth station located in Vernon Valley, New Jersey. The satellite payload design and performance are described. The principal spacecraft bus systems are described with emphasis on improvements made for operation in the inclined, elliptical geosynchronous orbits.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2015AGUFM.B53I..08D&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2015AGUFM.B53I..08D&link_type=ABSTRACT"><span id="translatedtitle">Advances in animal ecology from 3D ecosystem mapping with Li<span class="hlt">DAR</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Davies, A.; Asner, G. P.</p> <p>2015-12-01</p> <p>The advent and recent advances of Light Detection and Ranging (Li<span class="hlt">DAR</span>) have enabled accurate measurement of 3D ecosystem structure. Although the use of Li<span class="hlt">DAR</span> data is widespread in vegetation science, it has only recently (< 14 years) been applied to animal ecology. Despite such recent application, Li<span class="hlt">DAR</span> has enabled new insights in the field and revealed the fundamental importance of 3D ecosystem structure for animals. We reviewed the studies to date that have used Li<span class="hlt">DAR</span> in animal ecology, synthesising the insights gained. Structural heterogeneity is most conducive to increased animal richness and abundance, and increased complexity of vertical vegetation structure is more positively influential than traditionally measured canopy cover, which produces mixed results. However, different taxonomic groups interact with a variety of 3D canopy traits and some groups with 3D topography. Li<span class="hlt">DAR</span> technology can be applied to animal ecology studies in a wide variety of environments to answer an impressive array of questions. Drawing on case studies from vastly different groups, termites and lions, we further demonstrate the applicability of Li<span class="hlt">DAR</span> and highlight new understanding, ranging from habitat preference to predator-prey interactions, that would not have been possible from studies restricted to field based methods. We conclude with discussion of how future studies will benefit by using Li<span class="hlt">DAR</span> to consider 3D habitat effects in a wider variety of ecosystems and with more taxa to develop a better understanding of animal dynamics.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011AGUFMEP41A0585H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011AGUFMEP41A0585H"><span id="translatedtitle">Applications of High-Resolution Li<span class="hlt">DAR</span> Data for the Christina River Basin CZO</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Hicks, N. S.; Aufdenkampe, A. K.; Hicks, S. D.</p> <p>2011-12-01</p> <p>High-resolution Li<span class="hlt">DAR</span> data allows for fine scale geomorphic assessment over relatively large spatial extents. Previously available DEMs with a resolution of ten meters or more did not provide adequate resolution for geomorphic characterization of small streams and watersheds or the identification of changes in stream morphology over time. High-resolution Li<span class="hlt">DAR</span> data for a portion of the Christina River Basin Critical Zone Observatory (CRB-CZO) was obtained during both leaf-off and leaf-on time periods in 2010. Topographic data from these flights is being analyzed with the intent of geomorphic applications such as stream morphology, sediment transport studies, and the evaluation of alluvial deposits. These data and resultant products will also be used in hydrologic and biogeochemical modeling and in biologic and biogeochemical studies of these streams, which are long-term study sites. The Li<span class="hlt">DAR</span> data also facilitate informed instrument placement and will be used for vegetation studies. The Li<span class="hlt">DAR</span> data for the CRB-CZO has been used to create a variety of Li<span class="hlt">DAR</span> based topographic data products including TINs and 0.5-m DEMs. Li<span class="hlt">DAR</span> derived slope and elevation products were combined with Li<span class="hlt">DAR</span> intensity images to identify stream channel boundaries and stream centerlines for third through first-order streams. High-resolution slope data also aided in floodplain characterization of these small streams. These high precision stream channel and floodplain characterizations would not have been otherwise possible without extensive field surveying. Future Li<span class="hlt">DAR</span> flights will allow for the identification of changes in channel morphology over time in low order basins. These characterizations are of particular interest in comparisons between forested and meadow reaches, and in studying the effects of changes in land-use on channel morphology. High-resolution Li<span class="hlt">DAR</span> data allow for the generation of surface characterizations of importance to a wide range of interdisciplinary researchers.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2015JPRS..101..262Y&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2015JPRS..101..262Y&link_type=ABSTRACT"><span id="translatedtitle">Automatic registration of UAV-borne sequent images and Li<span class="hlt">DAR</span> data</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Yang, Bisheng; Chen, Chi</p> <p>2015-03-01</p> <p>Use of direct geo-referencing data leads to registration failure between sequent images and Li<span class="hlt">DAR</span> data captured by mini-UAV platforms because of low-cost sensors. This paper therefore proposes a novel automatic registration method for sequent images and Li<span class="hlt">DAR</span> data captured by mini-UAVs. First, the proposed method extracts building outlines from Li<span class="hlt">DAR</span> data and images and estimates the exterior orientation parameters (EoPs) of the images with building objects in the Li<span class="hlt">DAR</span> data coordinate framework based on corresponding corner points derived indirectly by using linear features. Second, the EoPs of the sequent images in the image coordinate framework are recovered using a structure from motion (SfM) technique, and the transformation matrices between the Li<span class="hlt">DAR</span> coordinate and image coordinate frameworks are calculated using corresponding EoPs, resulting in a coarse registration between the images and the Li<span class="hlt">DAR</span> data. Finally, 3D points are generated from sequent images by multi-view stereo (MVS) algorithms. Then the EoPs of the sequent images are further refined by registering the Li<span class="hlt">DAR</span> data and the 3D points using an iterative closest-point (ICP) algorithm with the initial results from coarse registration, resulting in a fine registration between sequent images and Li<span class="hlt">DAR</span> data. Experiments were performed to check the validity and effectiveness of the proposed method. The results show that the proposed method achieves high-precision robust co-registration of sequent images and Li<span class="hlt">DAR</span> data captured by mini-UAVs.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013EGUGA..15.5244G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013EGUGA..15.5244G"><span id="translatedtitle">Geomorphic change detection in small Alpine basins using Li<span class="hlt">DAR</span> DTMs</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Goldin, Beatrice; Cavalli, Marco; Comiti, Francesco; Marchi, Lorenzo</p> <p>2013-04-01</p> <p>Morphological change evaluation of earth surface is an important task in environmental monitoring. Methods devoted to the assessment of geomorphic changes can be used to identify geomorphologically unstable areas, to quantify processes intensity and to compute sediment budgets. Digital elevation models (DEMs) built from repeated topographic surveys can be used to produce DEM of Difference (DoD) maps and to estimate volumetric changes through time. Nowadays Li<span class="hlt">DAR</span> technology provides digital models representative of the bare earth surface (Digital Terrain Models - DTMs) at high spatial resolution and over large spatial extents, thus contributing to the increase of accuracy of morphometric and volumetric measurement of varying surfaces. In this study, high-resolution DTMs derived from airborne Li<span class="hlt">DAR</span> data acquired in different years (2006 and 2011) were used in order to characterize sediment transport processes such as debris flows and bedload transport in two small Alpine basins. Two DTMs (2 m resolution) were derived for the Gadria and Strimm catchments (Vinschgau-Venosta valley, Autonomous Province of Bozen-Bolzano, Italy). These basins, which cover, respectively, areas of 6.3 and 8.5 km2, have been chosen due to their contrasting morphology and because they feature different types and intensity of sediment transfer processes: Gadria channel is characterized by frequent occurrence of debris flows (almost one debris flow per year), whereas Strimm is essentially a bedload stream. A method based on fuzzy logic (Wheaton et <span class="hlt">al</span>., 2010), which takes into account DTM uncertainties, was used to derive the DoD of the study area. The comparison between the 2006 and 2011 DTMs permitted the assessment of morphometric changes at the basin scale over the 5 yrs period. The results of DoD analysis are consistent with field observations of erosion and sediment transport. Besides, the DoD proved useful to identify the relationship between erosion, deposition or no-change areas and</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20120001831','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20120001831"><span id="translatedtitle">Laboratory Shock Experiments on Basalt - Iron Sulfate Mixes at Approximately 40-50 GPa and Their Relevance to the Martian Regolith Component Present in <span class="hlt">Shergottites</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Rao, M. N.; Nyquist, L. E.; Ross, D. K.; Asimow, P. D.; See, T.; Sutton, S.; Cardernas, F.; Montes, R.; Cintala, M.</p> <p>2012-01-01</p> <p>Basaltic <span class="hlt">shergottites</span> such as Shergotty, Zagami and EET79001 contain impact melt glass pockets that are rich in Martian atmospheric gases [1] and are known as gas-rich impact-melt (GRIM) glasses. These glasses show evidence for the presence of a Martian regolith component based on Sm and Kr isotopic studies [2]. The GRIM glasses are sometimes embedded with clusters of innumerable micron-sized iron-sulfide blebs associated with minor amounts of iron sulfate particles [3, 4]. These sulfide blebs are secondary in origin and are not related to the primary igneous sulfides occurring in Martian meteorites. The material comprising these glasses arises from the highly oxidizing Martian surface and sulfur is unlikely to occur as sulfide in the Martian regoilith. Instead, sulfur is shown to occur as sulfate based on APXS and Mossbauer results obtained by the Opportunity and Spirit rovers at Meridiani and Gusev [5]. We have earlier suggested that the micron-sized iron sulfide globules in GRIM glasses were likely produced by shock-reduction of iron sulfate occurring in the regolith at the time when the GRIM glasses were produced by the meteoroid impact that launched the Martian meteorites into space [6]. As a result of high energy deposition by shock (approx. 40-60 GPa), the iron sulfate bearing phases are likely to melt along with other regolith components and will get reduced to immiscible sulfide fluid under reducing conditions. On quenching, this generates a dispersion of micron-scale sulfide blebs. The reducing agents in our case are likely to be H2 and CO which were shock-implanted from the Martian atmosphere into these glasses along with the noble gases. We conducted lab simulation experiments in the Lindhurst Laboratory of Experimental Geophysics at Caltech and the Experimental Impact Laboratory at JSC to test whether iron sulfide globules can be produced by impact-driven reduction of iron sulfate by subjecting Columbia River Basalt (CRB) and ferric sulfate mixtures to</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016EGUGA..1811295H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016EGUGA..1811295H"><span id="translatedtitle">4D Near Real-Time Environmental Monitoring Using Highly Temporal Li<span class="hlt">DAR</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Höfle, Bernhard; Canli, Ekrem; Schmitz, Evelyn; Crommelinck, Sophie; Hoffmeister, Dirk; Glade, Thomas</p> <p>2016-04-01</p> <p>The last decade has witnessed extensive applications of 3D environmental monitoring with the Li<span class="hlt">DAR</span> technology, also referred to as laser scanning. Although several automatic methods were developed to extract environmental parameters from Li<span class="hlt">DAR</span> point clouds, only little research has focused on highly multitemporal near real-time Li<span class="hlt">DAR</span> (4D-Li<span class="hlt">DAR</span>) for environmental monitoring. Large potential of applying 4D-Li<span class="hlt">DAR</span> is given for landscape objects with high and varying rates of change (e.g. plant growth) and also for phenomena with sudden unpredictable changes (e.g. geomorphological processes). In this presentation we will report on the most recent findings of the research projects 4DEMON (http://uni-heidelberg.de/4demon) and NoeSLIDE (https://geomorph.univie.ac.at/forschung/projekte/aktuell/noeslide/). The method development in both projects is based on two real-world use cases: i) Surface parameter derivation of agricultural crops (e.g. crop height) and ii) change detection of landslides. Both projects exploit the "full history" contained in the Li<span class="hlt">DAR</span> point cloud time series. One crucial initial step of 4D-Li<span class="hlt">DAR</span> analysis is the co-registration over time, 3D-georeferencing and time-dependent quality assessment of the Li<span class="hlt">DAR</span> point cloud time series. Due to the high amount of datasets (e.g. one full Li<span class="hlt">DAR</span> scan per day), the procedure needs to be performed fully automatically. Furthermore, the online near real-time 4D monitoring system requires to set triggers that can detect removal or moving of tie reflectors (used for co-registration) or the scanner itself. This guarantees long-term data acquisition with high quality. We will present results from a georeferencing experiment for 4D-Li<span class="hlt">DAR</span> monitoring, which performs benchmarking of co-registration, 3D-georeferencing and also fully automatic detection of events (e.g. removal/moving of reflectors or scanner). Secondly, we will show our empirical findings of an ongoing permanent Li<span class="hlt">DAR</span> observation of a landslide (Gresten</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2013AGUFMEP31C..06P&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2013AGUFMEP31C..06P&link_type=ABSTRACT"><span id="translatedtitle">How Well Can We Predict Salmonid Spawning Habitat with Li<span class="hlt">DAR</span>?</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Pfeiffer, A.; Finnegan, N. J.; Hayes, S.</p> <p>2013-12-01</p> <p>Suitable salmonid spawning habitat is, to a great extent, determined by physical, landscape driven characteristics such as channel morphology and grain size. Identifying reaches with high-quality spawning habitat is essential to restoration efforts in areas where salmonid species are endangered or threatened. While both predictions of suitable habitat and observations of utilized habitat are common in the literature, they are rarely combined. Here we exploit a unique combination of high-resolution Li<span class="hlt">DAR</span> data and seven years of 387 individually surveyed Coho and Steelhead redds in Scott Creek, a 77 km2 un-glaciated coastal California drainage in the Santa Cruz Mountains, to both make and test predictions of spawning habitat. Using a threshold channel assumption, we predict grain size throughout Scott Creek via a shear stress model that incorporates channel width, instead of height, using Manning's equation (Snyder et <span class="hlt">al</span>., 2013). Slope and drainage area are computed from a Li<span class="hlt">DAR</span>-derived DEM, and channel width is calculated via hydraulic modeling. Our results for median grain size predictions closely match median grain sizes (D50) measured in the field, with the majority of sites having predicted D50's within a factor of two of the observed values, especially for reaches with D50 > 0.02m. This success suggests that the threshold model used to predict grain size is appropriate for un-glaciated alluvial channel systems. However, it appears that grain size alone is not a strong predictor of salmon spawning. Reaches with a high (>0.1m) average predicted D50 do have lower redd densities, as expected based on spawning gravel sizes in the literature. However, reaches with lower (<0.1m) predicted D50 have a wide range of redd densities, suggesting that reach-average grain size alone cannot explain spawning site selection in the finer-grained reaches of Scott Creek. We turn to analysis of bedform morphology in order to explain the variation in redd density in the low</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014PhDT.......533S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014PhDT.......533S"><span id="translatedtitle">Frontiers in Using Li<span class="hlt">DAR</span> to Analyze Urban Landscape Heterogeneity</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Singh, Kunwar Krishna Veer</p> <p></p> <p>Light Detection and Ranging (Li<span class="hlt">DAR</span>) technology has facilitated extraordinary advances in our ability to remotely sense precise details of both built and natural environments. The inherent complexity of urban landscapes and the massive data volumes produced by Li<span class="hlt">DAR</span> require unique methodological considerations for big data remote sensing over large metropolitan regions. The heterogeneous landscapes of the rapidly urbanizing Charlotte Metropolitan Region of North Carolina provided an ideal testing ground for developing methods of analysis for urban ecosystems over large regional extents, including: (1) fusion of Li<span class="hlt">DAR</span> digital surface models (DSMs) with Landsat TM imagery to balance spatial resolution, data volume, and mapping accuracy of urban land covers, (2) comparison of Li<span class="hlt">DAR</span>-derived metrics to fine grain optical imagery -- and their integration -- for detecting forest understory plant invaders, and (3) data reduction techniques for computationally efficient estimation of aboveground woody biomass in urban forests. In Chapter 1, I examined tradeoffs between potential gains in mapping accuracy and computational costs by integrating DSMs (structural and intensity) extracted from Li<span class="hlt">DAR</span> with TM imagery and evaluating the degree to which TM, Li<span class="hlt">DAR</span>, and Li<span class="hlt">DAR</span>-TM fusion data discriminated land covers. I used Maximum Likelihood and Classification Tree algorithms to classify TM data, Li<span class="hlt">DAR</span> data, and Li<span class="hlt">DAR</span>-TM fusions. I assessed the relative contributions of Li<span class="hlt">DAR</span> DSMs to map classification accuracy and identified an optimal spatial resolution of Li<span class="hlt">DAR</span> DSMs for large area assessments of urban land cover. In Chapter 2, I analyzed combinations of datasets developed from categorized Li<span class="hlt">DAR</span>-derived variables (Overstory, Understory, Topography, and Overall Vegetation Characteristics) and IKONOS imagery ( Optical) to detect and map the understory plant invader, Ligustrum sinense, using Random Forest (RF) and logistic regression (LR) algorithms, and I assessed the relative</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/26192511','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/26192511"><span id="translatedtitle">Surface characteristics modeling and performance evaluation of urban building materials using Li<span class="hlt">DAR</span> data.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Li, Xiaolu; Liang, Yu</p> <p>2015-05-20</p> <p>Analysis of light detection and ranging (Li<span class="hlt">DAR</span>) intensity data to extract surface features is of great interest in remote sensing research. One potential application of Li<span class="hlt">DAR</span> intensity data is target classification. A new bidirectional reflectance distribution function (BRDF) model is derived for target characterization of rough and smooth surfaces. Based on the geometry of our coaxial full-waveform Li<span class="hlt">DAR</span> system, the integration method is improved through coordinate transformation to establish the relationship between the BRDF model and intensity data of Li<span class="hlt">DAR</span>. A series of experiments using typical urban building materials are implemented to validate the proposed BRDF model and integration method. The fitting results show that three parameters extracted from the proposed BRDF model can distinguish the urban building materials from perspectives of roughness, specular reflectance, and diffuse reflectance. A comprehensive analysis of these parameters will help characterize surface features in a physically rigorous manner. PMID:26192511</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_9");'>9</a></li> <li><a href="#" onclick='return showDiv("page_10");'>10</a></li> <li class="active"><span>11</span></li> <li><a href="#" onclick='return showDiv("page_12");'>12</a></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_11 --> <div id="page_12" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_10");'>10</a></li> <li><a href="#" onclick='return showDiv("page_11");'>11</a></li> <li class="active"><span>12</span></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="221"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2016EGUGA..1812855G&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2016EGUGA..1812855G&link_type=ABSTRACT"><span id="translatedtitle">Intraday monitoring of granitic exfoliation sheets with Li<span class="hlt">DAR</span> and thermal imaging (Yosemite Valley, California, USA)</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Guerin, Antoine; Derron, Marc-Henri; Jaboyedoff, Michel; Abellán, Antonio; Dubas, Olivier; Collins, Brian D.; Stock, Greg M.</p> <p>2016-04-01</p> <p>Rockfall activity in Yosemite Valley is often linked to the presence of exfoliation sheets associated with other structures such as faults, joints or geological contacts. Daily and seasonal temperature variations or freeze-thaw cycles may strongly promote crack propagation along discontinuities, ultimately leading to rockfalls (Stock et <span class="hlt">al</span>., 2013). However, little is known concerning the impact of thermal variations on rock face deformation, despite its occurrence at all times of year. To understand the influence of daily temperature fluctuations on the behavior of exfoliation joints (i.e., fractures separating exfoliation sheets), we carried out two different experiments in October 2015: (a) We first monitored a sub-vertical granodiorite flake (19 m by 4 m by 0.1 m ; Collins and Stock, 2014) for 24 consecutive hours using Li<span class="hlt">DAR</span> and infrared thermal sensors; (b) We monitored a rock cliff (60 m by 45 m) composed of tens of exfoliation sheets located on the southeast face of El Capitan (an ~1000-m-tall cliff located in western Yosemite Valley) for several hours (from 05:30 pm to 01:30 am) to investigate the diurnal cooling effect on rocks of different lithologies. To calibrate the raw apparent temperature measured by the thermal imager (FLIR T660 infrared camera), we fixed pieces of reflective paper (aluminum foil) and black duct tape on both monitored cliffs to measure the reflected temperature and the emissivity of the different rocks. In addition, ambient temperature and relative humidity readings were performed for each acquisition. We then compared the calibrated temperatures to the values registered by resistance temperature detectors (Pt100 sensors), also attached to the rock. Finally, we compared the millimeter scale deformations observed with Li<span class="hlt">DAR</span> to the values measured by manual crackmeters (standard analog comparators with springs) installed beforehand in the fractures. For the first experiment (24-hour monitoring), a series of measurements were carried</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20100028398','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20100028398"><span id="translatedtitle">Synergy of VSWIR and Li<span class="hlt">DAR</span> for Ecosystem Structure, Biomass, and Canopy Diversity</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Cook, Bruce D.; Asner, Gregory P.</p> <p>2010-01-01</p> <p>This slide presentation reviews the use of Visible ShortWave InfraRed (VSWIR) Imaging Spectrometer and Li<span class="hlt">DAR</span> to study ecosystem structure, biomass and canopy diversity. It is shown that the biophysical data from Li<span class="hlt">DAR</span> and biochemical information from hyperspectral remote sensing provides complementary data for: (1) describing spatial patterns of vegetation and biodiversity, (2) characterizing relationships between ecosystem form and function, and (3) detecting natural and human induced change that affects the biogeochemical cycles.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://pubs.er.usgs.gov/publication/70098139','USGSPUBS'); return false;" href="http://pubs.er.usgs.gov/publication/70098139"><span id="translatedtitle">Modeling marbled murrelet (Brachyramphus marmoratus) habitat using Li<span class="hlt">DAR</span>-derived canopy data</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Hagar, Joan C.; Eskelson, Bianca N.I.; Haggerty, Patricia K.; Nelson, S. Kim; Vesely, David G.</p> <p>2014-01-01</p> <p>Li<span class="hlt">DAR</span> (Light Detection And Ranging) is an emerging remote-sensing tool that can provide fine-scale data describing vertical complexity of vegetation relevant to species that are responsive to forest structure. We used Li<span class="hlt">DAR</span> data to estimate occupancy probability for the federally threatened marbled murrelet (Brachyramphus marmoratus) in the Oregon Coast Range of the United States. Our goal was to address the need identified in the Recovery Plan for a more accurate estimate of the availability of nesting habitat by developing occupancy maps based on refined measures of nest-strand structure. We used murrelet occupancy data collected by the Bureau of Land Management Coos Bay District, and canopy metrics calculated from discrete return airborne Li<span class="hlt">DAR</span> data, to fit a logistic regression model predicting the probability of occupancy. Our final model for stand-level occupancy included distance to coast, and 5 Li<span class="hlt">DAR</span>-derived variables describing canopy structure. With an area under the curve value (AUC) of 0.74, this model had acceptable discrimination and fair agreement (Cohen's κ = 0.24), especially considering that all sites in our sample were regarded by managers as potential habitat. The Li<span class="hlt">DAR</span> model provided better discrimination between occupied and unoccupied sites than did a model using variables derived from Gradient Nearest Neighbor maps that were previously reported as important predictors of murrelet occupancy (AUC = 0.64, κ = 0.12). We also evaluated Li<span class="hlt">DAR</span> metrics at 11 known murrelet nest sites. Two Li<span class="hlt">DAR</span>-derived variables accurately discriminated nest sites from random sites (average AUC = 0.91). Li<span class="hlt">DAR</span> provided a means of quantifying 3-dimensional canopy structure with variables that are ecologically relevant to murrelet nesting habitat, and have not been as accurately quantified by other mensuration methods.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4683686','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4683686"><span id="translatedtitle">The Krüppel-Like Factor <span class="hlt">Dar</span>1 Determines Multipolar Neuron Morphology</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Wang, Xin; Zhang, Macy W.; Kim, Jung Hwan; Macara, Ann Marie; Sterne, Gabriella; Yang, Tao</p> <p>2015-01-01</p> <p>Neurons typically assume multipolar, bipolar, or unipolar morphologies. Little is known about the mechanisms underlying the development of these basic morphological types. Here, we show that the Krüppel-like transcription factor <span class="hlt">Dar</span>1 determines the multipolar morphology of postmitotic neurons in Drosophila. <span class="hlt">Dar</span>1 is specifically expressed in multipolar neurons and loss of <span class="hlt">dar</span>1 gradually converts multipolar neurons into the bipolar or unipolar morphology without changing neuronal identity. Conversely, misexpression of <span class="hlt">Dar</span>1 or its mammalian homolog in unipolar and bipolar neurons causes them to assume multipolar morphologies. <span class="hlt">Dar</span>1 regulates the expression of several dynein genes and nuclear distribution protein C (nudC), which is an essential component of a specialized dynein complex that positions the nucleus in a cell. We further show that these genes are required for <span class="hlt">Dar</span>1-induced multipolar neuron morphology. <span class="hlt">Dar</span>1 likely functions as a terminal selector gene for the basic layout of neuron morphology by regulating both dendrite extension and the dendrite–nucleus coupling. SIGNIFICANCE STATEMENT The three basic morphological types of neurons—unipolar, bipolar, and multipolar—are important for information processing and wiring of neural circuits. Little progress has been made toward understanding the molecular and cellular programs that generate these types since their discovery over a century ago. It is generally assumed that basic morphological types of neurons are determined by the number of dendrites growing out from the cell body. Here, we show that this model alone is insufficient. We introduce the positioning of nucleus as a critical factor in this process and report that the transcription factor <span class="hlt">Dar</span>1 determines multipolar neuron morphology in postmitotic neurons by regulating genes involved in nuclear positioning. PMID:26490864</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015IJAEO..38..267S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015IJAEO..38..267S"><span id="translatedtitle">Detecting understory plant invasion in urban forests using Li<span class="hlt">DAR</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Singh, Kunwar K.; Davis, Amy J.; Meentemeyer, Ross K.</p> <p>2015-06-01</p> <p>Light detection and ranging (Li<span class="hlt">DAR</span>) data are increasingly used to measure structural characteristics of urban forests but are rarely used to detect the growing problem of exotic understory plant invaders. We explored the merits of using Li<span class="hlt">DAR</span>-derived metrics alone and through integration with spectral data to detect the spatial distribution of the exotic understory plant Ligustrum sinense, a rapidly spreading invader in the urbanizing region of Charlotte, North Carolina, USA. We analyzed regional-scale L. sinense occurrence data collected over the course of three years with Li<span class="hlt">DAR</span>-derived metrics of forest structure that were categorized into the following groups: overstory, understory, topography, and overall vegetation characteristics, and IKONOS spectral features - optical. Using random forest (RF) and logistic regression (LR) classifiers, we assessed the relative contributions of Li<span class="hlt">DAR</span> and IKONOS derived variables to the detection of L. sinense. We compared the top performing models developed for a smaller, nested experimental extent using RF and LR classifiers, and used the best overall model to produce a predictive map of the spatial distribution of L. sinense across our country-wide study extent. RF classification of Li<span class="hlt">DAR</span>-derived topography metrics produced the highest mapping accuracy estimates, outperforming IKONOS data by 17.5% and the integration of Li<span class="hlt">DAR</span> and IKONOS data by 5.3%. The top performing model from the RF classifier produced the highest kappa of 64.8%, improving on the parsimonious LR model kappa by 31.1% with a moderate gain of 6.2% over the county extent model. Our results demonstrate the superiority of Li<span class="hlt">DAR</span>-derived metrics over spectral data and fusion of Li<span class="hlt">DAR</span> and spectral data for accurately mapping the spatial distribution of the forest understory invader L. sinense.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/18313013','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/18313013"><span id="translatedtitle">Suicide in the <span class="hlt">Dar</span> es Salaam region, Tanzania, 2005.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Mgaya, Edward; Kazaura, Method R; Outwater, Anne; Kinabo, Lina</p> <p>2008-04-01</p> <p>Suicide surveillance was launched at the Muhimbili National Hospital mortuary in <span class="hlt">Dar</span> es Salaam Region, Tanzania from 1st January to 31st December, 2005 to determine its magnitude and characteristics. Following the WHO guidelines with minor modifications, information on sex, dates of birth and death, places of residence and death, occupation, reasons and means of suicide were collected. There were 65 (2.3 per 100,000 population) suicides recorded in 2005. The suicide rate for males was 3.4/100,000 and for females was 1.2/100,000 which maybe some of the lowest rates ever reported in the world. The mean age at suicide was 32.9 (SD=13.1) years. Males were about three times more likely to commit suicide as females. The main motive behind suicide was recorded for 26 (40%) victims as family-related and for 11 (17%) as health related. Although there was a wide range of ages at which people committed suicide, the average age seems to be very low. Since reasons for suicide are coated with family problems, strategies to improve awareness of psychological and mental health services and to provide alternative economic and social support networks are advocated. PMID:18313013</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2016M%26PS...51..390S&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2016M%26PS...51..390S&link_type=ABSTRACT"><span id="translatedtitle">Determination of volatile concentrations in fluorapatite of Martian <span class="hlt">shergottite</span> NWA 2975 by combining synchrotron FTIR, Raman spectroscopy, EMPA, and TEM, and inferences on the volatile budget of the apatite host-magma</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>SłAby, Ewa; Koch-Müller, Monika; FöRster, Hans-Jürgen; Wirth, Richard; Rhede, Dieter; Schreiber, Anja; Schade, Ulrich</p> <p>2016-02-01</p> <p>We combined the focused ion beam sample preparation technique with polarized synchrotron-based FTIR (Fourier transform infrared) spectroscopy, laser-Raman spectroscopy, electron microprobe analysis (EMPA), and transmission electron microscope (TEM) analysis to identify and quantify structurally bound OH, F, Cl, and CO3 groups in fluorapatite from the Northwest Africa 2975 (NWA 2975) <span class="hlt">shergottite</span>. In this study, the first FTIR spectra of the OH-stretching region from a Martian apatite are presented that show characteristic OH-bands of a F-rich, hydroxyl-bearing apatite. Depending on the method of apatite-formula calculation and whether charge balance is assumed or not, the FTIR-based quantification of the incorporated OH, expressed as wt% H2O, is in variably good agreement with the H2O concentration calculated from electron microprobe data. EMP analyses yielded between 0.35 and 0.54 wt% H2O, and IR data yielded an average H2O content of 0.31 ± 0.03 wt%, consistent with the lower range determined from EMP analyses. The TEM observations implied that the volatiles budget of fluorapatite is magmatic. The water content and the relative volatile ratios calculated for the NWA 2975 magma are similar to those established for other enriched or intermediate <span class="hlt">shergottites</span>. It is difficult to define the source of enrichment: either Martian wet mantle or crustal assimilation. Comparing the environment of parental magma generation for NWA 2975 with the terrestrial mantle in terms of water content, it displays a composition intermediate between enriched and depleted MORB.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2008AGUFMIN51A1146C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2008AGUFMIN51A1146C"><span id="translatedtitle">A Cyberinfrastructure Platform for Distribution of GeoEarthScope Li<span class="hlt">DAR</span> Topography Data</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Crosby, C. J.; Nandigam, V.; Arrowsmith, J. R.; Balakrishnan, S.; Alex, N.; Baru, C.</p> <p>2008-12-01</p> <p>The recently completed GeoEarthScope airborne Li<span class="hlt">DAR</span> (Light Detection And Ranging) topography acquisition will provide unprecedented data adjacent to active faults throughout the plate boundary region of western North America. Totaling more than 5000 square kilometers, these community-oriented data offer an high-resolution representation of fault zone topography and should be a revolutionary resource for researchers studying earthquake hazards, active faulting, landscape processes, and ground deformation. Since spring of 2007, the NSF-funded GeoEarthScope Li<span class="hlt">DAR</span> project has acquired data for the San Andreas fault system in northern California, faults in southern California, the Yakima Fold and Thrust Belt in Washington, Yellowstone National Park, the Tetons, the Wasatch Front, and Alaska. These data will be made available via the OpenTopography Portal (www.opentopography.org), a domain-specific component of the GEON project, as they are processed and delivered by the National Center for Airborne Laser Mapping. The OpenTopography Portal (OpenToPo) provides access to a variety of GeoEarthScope Li<span class="hlt">DAR</span> data products and uses several cyberinfrastructure components developed by the GEON project. These products range from simple Google Earth visualizations of Li<span class="hlt">DAR</span> hillshades to standard digital elevation model (DEM) products as well as Li<span class="hlt">DAR</span> point cloud data. The wide spectrum of Li<span class="hlt">DAR</span> users have variable scientific applications, computing resources and technical experience and thus require a data distribution system that provides various levels of access to the data. Standard DEM products in OpenToPo are accessed via a Google Map and/or Google Earth-based interface that allow users to browse and download the data products. For users who wish to explore the full potential of the Li<span class="hlt">DAR</span> data, we provide access to the raw Li<span class="hlt">DAR</span> point data and a suite of DEM generation tools to enable users to create custom DEMs to best fit their science applications. Storage and management of</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2016ISPAr41B3..441Y&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2016ISPAr41B3..441Y&link_type=ABSTRACT"><span id="translatedtitle">Classification of Li<span class="hlt">DAR</span> Data with Point Based Classification Methods</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Yastikli, N.; Cetin, Z.</p> <p>2016-06-01</p> <p>Li<span class="hlt">DAR</span> is one of the most effective systems for 3 dimensional (3D) data collection in wide areas. Nowadays, airborne Li<span class="hlt">DAR</span> data is used frequently in various applications such as object extraction, 3D modelling, change detection and revision of maps with increasing point density and accuracy. The classification of the Li<span class="hlt">DAR</span> points is the first step of Li<span class="hlt">DAR</span> data processing chain and should be handled in proper way since the 3D city modelling, building extraction, DEM generation, etc. applications directly use the classified point clouds. The different classification methods can be seen in recent researches and most of researches work with the gridded Li<span class="hlt">DAR</span> point cloud. In grid based data processing of the Li<span class="hlt">DAR</span> data, the characteristic point loss in the Li<span class="hlt">DAR</span> point cloud especially vegetation and buildings or losing height accuracy during the interpolation stage are inevitable. In this case, the possible solution is the use of the raw point cloud data for classification to avoid data and accuracy loss in gridding process. In this study, the point based classification possibilities of the Li<span class="hlt">DAR</span> point cloud is investigated to obtain more accurate classes. The automatic point based approaches, which are based on hierarchical rules, have been proposed to achieve ground, building and vegetation classes using the raw Li<span class="hlt">DAR</span> point cloud data. In proposed approaches, every single Li<span class="hlt">DAR</span> point is analyzed according to their features such as height, multi-return, etc. then automatically assigned to the class which they belong to. The use of un-gridded point cloud in proposed point based classification process helped the determination of more realistic rule sets. The detailed parameter analyses have been performed to obtain the most appropriate parameters in the rule sets to achieve accurate classes. The hierarchical rule sets were created for proposed Approach 1 (using selected spatial-based and echo-based features) and Approach 2 (using only selected spatial-based features</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013AGUFM.V13E2651R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013AGUFM.V13E2651R"><span id="translatedtitle">A Li<span class="hlt">DAR</span> Survey of an Exposed Magma Plumbing System in the San Rafael Desert, Utah</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Richardson, J. A.; Kinman, S.; Connor, L.; Connor, C.; Wetmore, P. H.</p> <p>2013-12-01</p> <p>Fields of dozens to hundreds of volcanoes are a common occurrence on Earth and are created due to distributed-style volcanism often referred to as "monogenetic." These volcanic fields represent a significant hazard on both local and regional scales. While it is important to understand the physical states of active volcanic fields, it is difficult or impossible to directly observe active magma emplacement. Because of this, observing an exposed magmatic plumbing system may enable further efforts to describe active volcanic fields. The magmatic plumbing system of a Pliocene-aged monogenetic volcanic field is currently exposed as a sill and dike swarm in the San Rafael Desert of Central Utah. Alkali diabase and shonkinitic sills and dikes in this region intruded into Mesozoic sedimentary units of the Colorado Plateau and now make up the most erosion resistant units, forming mesas, ridges, and small peaks associated with sills, dikes, and plug-like bodies respectively. Diez et <span class="hlt">al</span>. (Lithosphere, 2009) and Kiyosugi et <span class="hlt">al</span>. (Geology, 2012) provide evidence that each cylindrical plug-like body represents a conduit that once fed one volcano. The approximate original depth of the currently exposed swarm is estimated to be 0.8 km. Volcanic and sedimentary materials may be discriminated at very high resolution with the use of Light Detection and Ranging (Li<span class="hlt">DAR</span>). Li<span class="hlt">DAR</span> produces a three dimensional point cloud, where each point has an associated return intensity. High resolution, bare earth digital elevation models (DEMs) can be produced after vegetation is identified and removed from the dataset. The return intensity at each point can enable classification as either sedimentary or volcanic rock. A Terrestrial Li<span class="hlt">DAR</span> Survey (TLS) has been carried out to map a large hill with at least one volcanic conduit at its core. This survey implements a RIEGL VZ-400 3D Laser Scanner, which successfully maps solid objects in line-of-sight and within 600 meters. The laser used has a near</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2016IJAEO..50..150L&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2016IJAEO..50..150L&link_type=ABSTRACT"><span id="translatedtitle">Retrieval of effective leaf area index (LAIe) and leaf area density (LAD) profile at individual tree level using high density multi-return airborne Li<span class="hlt">DAR</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Lin, Yi; West, Geoff</p> <p>2016-08-01</p> <p>As an important canopy structure indicator, leaf area index (LAI) proved to be of considerable implications for forest ecosystem and ecological studies, and efficient techniques for accurate LAI acquisitions have long been highlighted. Airborne light detection and ranging (Li<span class="hlt">DAR</span>), often termed as airborne laser scanning (<span class="hlt">ALS</span>), once was extensively investigated for this task but showed limited performance due to its low sampling density. Now, <span class="hlt">ALS</span> systems exhibit more competing capacities such as high density and multi-return sampling, and hence, people began to ask the questions like-"can <span class="hlt">ALS</span> now work better on the task of LAI prediction?" As a re-examination, this study investigated the feasibility of LAI retrievals at the individual tree level based on high density and multi-return <span class="hlt">ALS</span>, by directly considering the vertical distributions of laser points lying within each tree crown instead of by proposing feature variables such as quantiles involving laser point distribution modes at the plot level. The examination was operated in the case of four tree species (i.e. Picea abies, Pinus sylvestris, Populus tremula and Quercus robur) in a mixed forest, with their LAI-related reference data collected by using static terrestrial laser scanning (TLS). In light of the differences between <span class="hlt">ALS</span>- and TLS-based LAI characterizations, the methods of voxelization of 3D scattered laser points, effective LAI (LAIe) that does not distinguish branches from canopies and unified cumulative LAI (ucLAI) that is often used to characterize the vertical profiles of crown leaf area densities (LADs) was used; then, the relationships between the <span class="hlt">ALS</span>- and TLS-derived LAIes were determined, and so did ucLAIs. Tests indicated that the tree-level LAIes for the four tree species can be estimated based on the used airborne Li<span class="hlt">DAR</span> (R2 = 0.07, 0.26, 0.43 and 0.21, respectively) and their ucLAIs can also be derived. Overall, this study has validated the usage of the contemporary high density multi</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013EGUGA..1511160C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013EGUGA..1511160C"><span id="translatedtitle">Inside and around the roman town of Grumentum: the contribution of Li<span class="hlt">DAR</span> and historical air photography</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Cianciarulo, Dario; Guariglia, Annibale; Lasaponara, Rosa; Masini, Nicola</p> <p>2013-04-01</p> <p>The papers deals with the integration of aerial laser scanning, multitemporal satellite and aerial dataset to provide information on the 'forma urbis' of the Grumentum roman town, to detect new archaeological features in its close surrounding and to analyze changes of the landscape over the time. Grumentum is an ancient town, 50 km south of Potenza (Southern Italy), located near the 'Via Herculea' connecting Venusia, in the north est of Basilicata, with Heraclea in the Ionian coast. The first settlement date back to the 6th century BC. Then, it was resettled by the Romans in the 3rd century BC. The town, which evidences a long history from the Republican age to late Antiquity (III BC-V AD), is characterized by the typical urban pattern of 'cardi' and 'decumani'. Its excavated ruins include a large amphitheatre, a theatre, the thermae, the Forum and some temples. Li<span class="hlt">DAR</span> data, adequately filtered, classified and post processed by using geostatistics methods(Lasaponara et <span class="hlt">al</span>. 2012), enabled to detect features linked to tombs under a dense vegetation located close to the urban perimeter. The analysis of historical air photos, draped over the ground surface obtained from the Li<span class="hlt">DAR</span> survey, put in evidence some unknown crop-marks linked to roman urban fabric. Finally, the same photos along with the satellite multitemporal dataset allowed us to reconstruct the recent history of the landscape from the Agrarian Reform, in the 50s, up today. Reference Lasaponara R., Masini N., Holmgren R., Backe Forsberg Y., Integration of aerial and satellite remote sensing for archaeological investigations: a case study of the Etruscan site San Giovenale, Journal of Geophysics and Engineering, vol. 9, S26-S39, doi:10.1088/1742-2132/9/4/S26</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/24663850','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/24663850"><span id="translatedtitle">Estimating FPAR of maize canopy using airborne discrete-return Li<span class="hlt">DAR</span> data.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Luo, Shezhou; Wang, Cheng; Xi, Xiaohuan; Pan, Feifei</p> <p>2014-03-10</p> <p>The fraction of absorbed photosynthetically active radiation (FPAR) is a key parameter for ecosystem modeling, crop growth monitoring and yield prediction. Ground-based FPAR measurements are time consuming and labor intensive. Remote sensing provides an alternative method to obtain repeated, rapid and inexpensive estimates of FPAR over large areas. Li<span class="hlt">DAR</span> is an active remote sensing technology and can be used to extract accurate canopy structure parameters. A method to estimating FPAR of maize from airborne discrete-return Li<span class="hlt">DAR</span> data was developed and tested in this study. The raw Li<span class="hlt">DAR</span> point clouds were processed to separate ground returns from vegetation returns using a filter method over a maize field in the Heihe River Basin, northwest China. The fractional cover (fCover) of maize canopy was computed using the ratio of canopy return counts or intensity sums to the total of returns or intensities. FPAR estimation models were established based on linear regression analysis between the Li<span class="hlt">DAR</span>-derived fCover and the field-measured FPAR (R(2) = 0.90, RMSE = 0.032, p < 0.001). The reliability of the constructed regression model was assessed using the leave-one-out cross-validation procedure and results show that the regression model is not overfitting the data and has a good generalization capability. Finally, 15 independent field-measured FPARs were used to evaluate accuracy of the Li<span class="hlt">DAR</span>-predicted FPARs and results show that the Li<span class="hlt">DAR</span>-predicted FPAR has a high accuracy (R(2) = 0.89, RMSE = 0.034). In summary, this study suggests that the airborne discrete-return Li<span class="hlt">DAR</span> data could be adopted to accurately estimate FPAR of maize. PMID:24663850</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/20697878','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/20697878"><span id="translatedtitle">Estimation of effective plant area index for South Korean forests using Li<span class="hlt">DAR</span> system.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Kwak, Doo-Ahn; Lee, Woo-Kyun; Kafatos, Menas; Son, Yowhan; Cho, Hyun-Kook; Lee, Seung-Ho</p> <p>2010-07-01</p> <p>Light Detection and Ranging (Li<span class="hlt">DAR</span>) systems can be used to estimate both vertical and horizontal forest structure. Woody components, the leaves of trees and the understory can be described with high precision, using geo-registered 3D-points. Based on this concept, the Effective Plant Area Indices (PAI(e)) for areas of Korean Pine (Pinus koraiensis), Japanese Larch (Larix leptolepis) and Oak (Quercus spp.) were estimated by calculating the ratio of intercepted and incident LIDAR laser rays for the canopies of the three forest types. Initially, the canopy gap fraction (G ( Li<span class="hlt">DAR</span> )) was generated by extracting the Li<span class="hlt">DAR</span> data reflected from the canopy surface, or inner canopy area, using k-means statistics. The Li<span class="hlt">DAR</span>-derived PAI(e) was then estimated by using G ( LIDAR ) with the Beer-Lambert law. A comparison of the Li<span class="hlt">DAR</span>-derived and field-derived PAI(e) revealed the coefficients of determination for Korean Pine, Japanese Larch and Oak to be 0.82, 0.64 and 0.59, respectively. These differences between field-based and LIDAR-based PAI(e) for the different forest types were attributed to the amount of leaves and branches in the forest stands. The absence of leaves, in the case of both Larch and Oak, meant that the Li<span class="hlt">DAR</span> pulses were only reflected from branches. The probability that the Li<span class="hlt">DAR</span> pulses are reflected from bare branches is low as compared to the reflection from branches with a high leaf density. This is because the size of the branch is smaller than the resolution across and along the 1 meter LIDAR laser track. Therefore, a better predictive accuracy would be expected for the model if the study would be repeated in late spring when the shoots and leaves of the deciduous trees begin to appear. PMID:20697878</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015JPRS..101..310S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015JPRS..101..310S"><span id="translatedtitle">Effects of Li<span class="hlt">DAR</span> point density and landscape context on estimates of urban forest biomass</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Singh, Kunwar K.; Chen, Gang; McCarter, James B.; Meentemeyer, Ross K.</p> <p>2015-03-01</p> <p>Light Detection and Ranging (Li<span class="hlt">DAR</span>) data is being increasingly used as an effective alternative to conventional optical remote sensing to accurately estimate aboveground forest biomass ranging from individual tree to stand levels. Recent advancements in Li<span class="hlt">DAR</span> technology have resulted in higher point densities and improved data accuracies accompanied by challenges for procuring and processing voluminous Li<span class="hlt">DAR</span> data for large-area assessments. Reducing point density lowers data acquisition costs and overcomes computational challenges for large-area forest assessments. However, how does lower point density impact the accuracy of biomass estimation in forests containing a great level of anthropogenic disturbance? We evaluate the effects of Li<span class="hlt">DAR</span> point density on the biomass estimation of remnant forests in the rapidly urbanizing region of Charlotte, North Carolina, USA. We used multiple linear regression to establish a statistical relationship between field-measured biomass and predictor variables derived from Li<span class="hlt">DAR</span> data with varying densities. We compared the estimation accuracies between a general Urban Forest type and three Forest Type models (evergreen, deciduous, and mixed) and quantified the degree to which landscape context influenced biomass estimation. The explained biomass variance of the Urban Forest model, using adjusted R2, was consistent across the reduced point densities, with the highest difference of 11.5% between the 100% and 1% point densities. The combined estimates of Forest Type biomass models outperformed the Urban Forest models at the representative point densities (100% and 40%). The Urban Forest biomass model with development density of 125 m radius produced the highest adjusted R2 (0.83 and 0.82 at 100% and 40% Li<span class="hlt">DAR</span> point densities, respectively) and the lowest RMSE values, highlighting a distance impact of development on biomass estimation. Our evaluation suggests that reducing Li<span class="hlt">DAR</span> point density is a viable solution to regional</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014TCD.....8.3141H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014TCD.....8.3141H"><span id="translatedtitle">Independent evaluation of the SNODAS snow depth product using regional scale Li<span class="hlt">DAR</span>-derived measurements</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Hedrick, A.; Marshall, H.-P.; Winstral, A.; Elder, K.; Yueh, S.; Cline, D.</p> <p>2014-06-01</p> <p>Repeated Light Detection and Ranging (Li<span class="hlt">DAR</span>) surveys are quickly becoming the de facto method for measuring spatial variability of montane snowpacks at high resolution. This study examines the potential of a 750 km2 Li<span class="hlt">DAR</span>-derived dataset of snow depths, collected during the 2007 northern Colorado Cold Lands Processes Experiment (CLPX-2), as a validation source for an operational hydrologic snow model. The SNOw Data Assimilation System (SNODAS) model framework, operated by the US National Weather Service, combines a physically-based energy-and-mass-balance snow model with satellite, airborne and automated ground-based observations to provide daily estimates of snowpack properties at nominally 1 km resolution over the coterminous United States. Independent validation data is scarce due to the assimilating nature of SNODAS, compelling the need for an independent validation dataset with substantial geographic coverage. Within twelve distinctive 500 m × 500 m study areas located throughout the survey swath, ground crews performed approximately 600 manual snow depth measurements during each of the CLPX-2 Li<span class="hlt">DAR</span> acquisitions. This supplied a dataset for constraining the uncertainty of upscaled Li<span class="hlt">DAR</span> estimates of snow depth at the 1 km SNODAS resolution, resulting in a root-mean-square difference of 13 cm. Upscaled Li<span class="hlt">DAR</span> snow depths were then compared to the SNODAS-estimates over the entire study area for the dates of the Li<span class="hlt">DAR</span> flights. The remotely-sensed snow depths provided a more spatially continuous comparison dataset and agreed more closely to the model estimates than that of the in situ measurements alone. Finally, the results revealed three distinct areas where the differences between Li<span class="hlt">DAR</span> observations and SNODAS estimates were most drastic, suggesting natural processes specific to these regions as causal influences on model uncertainty.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2009JGRG..114.0E04H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2009JGRG..114.0E04H"><span id="translatedtitle">Improved estimates of forest vegetation structure and biomass with a Li<span class="hlt">DAR</span>-optimized sampling design</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Hawbaker, Todd J.; Keuler, Nicholas S.; Lesak, Adrian A.; Gobakken, Terje; Contrucci, Kirk; Radeloff, Volker C.</p> <p>2009-06-01</p> <p>Li<span class="hlt">DAR</span> data are increasingly available from both airborne and spaceborne missions to map elevation and vegetation structure. Additionally, global coverage may soon become available with NASA's planned DESDynI sensor. However, substantial challenges remain to using the growing body of Li<span class="hlt">DAR</span> data. First, the large volumes of data generated by Li<span class="hlt">DAR</span> sensors require efficient processing methods. Second, efficient sampling methods are needed to collect the field data used to relate Li<span class="hlt">DAR</span> data with vegetation structure. In this paper, we used low-density Li<span class="hlt">DAR</span> data, summarized within pixels of a regular grid, to estimate forest structure and biomass across a 53,600 ha study area in northeastern Wisconsin. Additionally, we compared the predictive ability of models constructed from a random sample to a sample stratified using mean and standard deviation of Li<span class="hlt">DAR</span> heights. Our models explained between 65 to 88% of the variability in DBH, basal area, tree height, and biomass. Prediction errors from models constructed using a random sample were up to 68% larger than those from the models built with a stratified sample. The stratified sample included a greater range of variability than the random sample. Thus, applying the random sample model to the entire population violated a tenet of regression analysis; namely, that models should not be used to extrapolate beyond the range of data from which they were constructed. Our results highlight that Li<span class="hlt">DAR</span> data integrated with field data sampling designs can provide broad-scale assessments of vegetation structure and biomass, i.e., information crucial for carbon and biodiversity science.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2013AGUFM.B31A0356M&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2013AGUFM.B31A0356M&link_type=ABSTRACT"><span id="translatedtitle">Li<span class="hlt">DAR</span> Applications in Resource Geology and Benefits for Land Management</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Mikulovsky, R. P.; De La Fuente, J. A.</p> <p>2013-12-01</p> <p>The US Forest Service (US Department of Agriculture) manages a broad range of geologic resources and hazards on National Forests and Grass Lands throughout the United States. Resources include rock and earth materials, groundwater, caves and paleontological resources, minerals, energy resources, and unique geologic areas. Hazards include landslides, floods, earthquakes, volcanic eruptions, and naturally hazardous materials (e.g., asbestos, radon). Forest Service Geologists who address these issues are Resource Geologists. They have been exploring Li<span class="hlt">DAR</span> as a revolutionary tool to efficiently manage all of these hazards and resources. However, most Li<span class="hlt">DAR</span> applications for management have focused on timber and fuels management, rather than landforms. This study shows the applications and preliminary results of using Li<span class="hlt">DAR</span> for managing geologic resources and hazards on public lands. Applications shown include calculating sediment budgets, mapping and monitoring landslides, mapping and characterizing borrow pits or mines, determining landslide potential, mapping faults, and characterizing groundwater dependent ecosystems. Li<span class="hlt">DAR</span> can be used to model potential locations of groundwater dependent ecosystems with threatened or endangered plant species such as Howellia aquatilis. This difficult to locate species typically exists on the Mendocino National Forest within sag ponds on landslide benches. Li<span class="hlt">DAR</span> metrics of known sites are used to model potential habitat. Thus Li<span class="hlt">DAR</span> can link the disciplines of geology, hydrology, botany, archaeology and others for enhanced land management. As Li<span class="hlt">DAR</span> acquisition costs decrease and it becomes more accessible, land management organizations will find a wealth of applications with potential far-reaching benefits for managing geologic resources and hazards.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010PhDT.......136L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010PhDT.......136L"><span id="translatedtitle">Geotechnical applications of Li<span class="hlt">DAR</span> pertaining to geomechanical evaluation and hazard identification</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Lato, Matthew J.</p> <p></p> <p>Natural hazards related to ground movement that directly affect the safety of motorists and highway infrastructure include, but are not limited to, rockfalls, rockslides, debris flows, and landslides. This thesis specifically deals with the evaluation of rockfall hazards through the evaluation of Li<span class="hlt">DAR</span> data. Light Detection And Ranging (Li<span class="hlt">DAR</span>) is an imaging technology that can be used to delineate and evaluate geomechanically-controlled hazards. Li<span class="hlt">DAR</span> has been adopted to conduct hazard evaluations pertaining to rockfall, rock-avalanches, debris flows, and landslides. Characteristics of Li<span class="hlt">DAR</span> surveying, such as rapid data acquisition rates, mobile data collection, and high data densities, pose problems to traditional CAD or GIS-based mapping methods. New analyses methods, including tools specifically oriented to geomechanical analyses, are needed. The research completed in this thesis supports development of new methods, including improved survey techniques, innovative software workflows, and processing algorithms to aid in the detection and evaluation of geomechanically controlled rockfall hazards. The scientific research conducted between the years of 2006-2010, as presented in this thesis, are divided into five chapters, each of which has been published by or is under review by an international journal. The five research foci are: (i) geomechanical feature extraction and analysis using Li<span class="hlt">DAR</span> data in active mining environments; (ii) engineered monitoring of rockfall hazards along transportation corridors: using mobile terrestrial Li<span class="hlt">DAR</span>; (iii) optimization of Li<span class="hlt">DAR</span> scanning and processing for automated structural evaluation of discontinuities in rockmasses; (iv) location orientation bias when using static Li<span class="hlt">DAR</span> data for geomechanical analysis; and (v) evaluating roadside rockmasses for rockfall hazards from Li<span class="hlt">DAR</span> data: optimizing data collection and processing protocols. The research conducted pertaining to this thesis has direct and significant implications with</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/21563587','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/21563587"><span id="translatedtitle">Spinning a laser web: predicting spider distributions using Li<span class="hlt">DAR</span>.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Vierling, K T; Bässler, C; Brandl, R; Vierling, L A; Weiss, I; Müller, J</p> <p>2011-03-01</p> <p>Li<span class="hlt">DAR</span> remote sensing has been used to examine relationships between vertebrate diversity and environmental characteristics, but its application to invertebrates has been limited. Our objectives were to determine whether Li<span class="hlt">DAR</span>-derived variables could be used to accurately describe single-species distributions and community characteristics of spiders in remote forested and mountainous terrain. We collected over 5300 spiders across multiple transects in the Bavarian National Park (Germany) using pitfall traps. We examined spider community characteristics (species richness, the Shannon index, the Simpson index, community composition, mean body size, and abundance) and single-species distribution and abundance with Li<span class="hlt">DAR</span> variables and ground-based measurements. We used the R2 and partial R2 provided by variance partitioning to evaluate the predictive power of Li<span class="hlt">DAR</span>-derived variables compared to ground measurements for each of the community characteristics. The total adjusted R2 for species richness, the Shannon index, community species composition, and body size had a range of 25-57%. Li<span class="hlt">DAR</span> variables and ground measurements both contributed >80% to the total predictive power. For species composition, the explained variance was approximately 32%, which was significantly greater than expected by chance. The predictive power of Li<span class="hlt">DAR</span>-derived variables was comparable or superior to that of the ground-based variables for examinations of single-species distributions, and it explained up to 55% of the variance. The predictability of species distributions was higher for species that had strong associations with shade in open-forest habitats, and this niche position has been well documented across the European continent for spider species. The similar statistical performance between Li<span class="hlt">DAR</span> and ground-based measures at our field sites indicated that deriving spider community and species distribution information using Li<span class="hlt">DAR</span> data can provide not only high predictive power at</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_10");'>10</a></li> <li><a href="#" onclick='return showDiv("page_11");'>11</a></li> <li class="active"><span>12</span></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_12 --> <div id="page_13" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_11");'>11</a></li> <li><a href="#" onclick='return showDiv("page_12");'>12</a></li> <li class="active"><span>13</span></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="241"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010EGUGA..1213613D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010EGUGA..1213613D"><span id="translatedtitle">Automated Detection of Geomorphic Features in Li<span class="hlt">DAR</span> Point Clouds of Various Spatial Density</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Dorninger, Peter; Székely, Balázs; Zámolyi, András.; Nothegger, Clemens</p> <p>2010-05-01</p> <p> relevant results. Consequently, it could be verified that a topographic surface can be properly represented by a set of distinct planar structures. Therefore, the subsequent interpretation of those planes with respect to geomorphic characteristics is acceptable. The additional in situ geological measurements verified some of our findings in the sense that similar primary directions could be found that were derived from the Li<span class="hlt">DAR</span> data set and (Zámolyi et <span class="hlt">al</span>., 2010, this volume). References: P. Dorninger, N. Pfeifer: "A Comprehensive Automated 3D Approach for Building Extraction, Reconstruction, and Regularization from Airborne Laser Scanning Point Clouds"; Sensors, 8 (2008), 11; 7323 - 7343. C. Nothegger, P. Dorninger: "3D Filtering of High-Resolution Terrestrial Laser Scanner Point Clouds for Cultural Heritage Documentation"; Photogrammetrie, Fernerkundung, Geoinformation, 1 (2009), 53 - 63. A. Zámolyi, B. Székely, G. Molnár, A. Roncat, P. Dorninger, A. Pocsai, M. Wyszyski, P. Drexel: "Comparison of Li<span class="hlt">DAR</span> derived directional topographic features with geologic field evidence: a case study of Doren landslide (Vorarlberg, Austria)"; EGU General Assembly 2010, Vienna, Austria</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014IJAEO..26..119G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014IJAEO..26..119G"><span id="translatedtitle">Evolutionary feature selection to estimate forest stand variables using Li<span class="hlt">DAR</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Garcia-Gutierrez, Jorge; Gonzalez-Ferreiro, Eduardo; Riquelme-Santos, Jose C.; Miranda, David; Dieguez-Aranda, Ulises; Navarro-Cerrillo, Rafael M.</p> <p>2014-02-01</p> <p>Light detection and ranging (Li<span class="hlt">DAR</span>) has become an important tool in forestry. Li<span class="hlt">DAR</span>-derived models are mostly developed by means of multiple linear regression (MLR) after stepwise selection of predictors. An increasing interest in machine learning and evolutionary computation has recently arisen to improve regression use in Li<span class="hlt">DAR</span> data processing. Although evolutionary machine learning has already proven to be suitable for regression, evolutionary computation may also be applied to improve parametric models such as MLR. This paper provides a hybrid approach based on joint use of MLR and a novel genetic algorithm for the estimation of the main forest stand variables. We show a comparison between our genetic approach and other common methods of selecting predictors. The results obtained from several Li<span class="hlt">DAR</span> datasets with different pulse densities in two areas of the Iberian Peninsula indicate that genetic algorithms perform better than the other methods statistically. Preliminary studies suggest that a lack of parametric conditions in field data and possible misuse of parametric tests may be the main reasons for the better performance of the genetic algorithm. This research confirms the findings of previous studies that outline the importance of evolutionary computation in the context of Li<span class="hlt">DAR</span> analisys of forest data, especially when the size of fieldwork datatasets is reduced.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2014E%26ES...18a2050S&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2014E%26ES...18a2050S&link_type=ABSTRACT"><span id="translatedtitle">Specular and diffuse object extraction from a Li<span class="hlt">DAR</span> derived Digital Surface Model (DSM)</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Saraf, N. M.; Hamid, J. R. A.; Kamaruddin, M. H.</p> <p>2014-02-01</p> <p>This paper intents to investigate the indifferent behaviour quantitatively of target objects of interest due to specular and diffuse reflectivity based on generated Li<span class="hlt">DAR</span> DSM of the study site in Ampang, Kuala Lumpur. The Li<span class="hlt">DAR</span> data to be used was initially checked for its reliability and accuracy. The point cloud Li<span class="hlt">DAR</span> data was converted to raster to allow grid analysis of the next process of generating the DSM and DTM. Filtering and masking were made removing the features of interest (i.e. building and tree) and other unwanted above surface features. A normalised DSM and object segmentation approach were conducted on the trees and buildings separately. Error assessment and findings attained were highlighted and documented. The result of Li<span class="hlt">DAR</span> verification certified that the data is reliable and useable. The RMSE obtained is within the tolerance value of horizontal and vertical accuracy (x, y, z) i.e. 0.159 m, 0.211 m 0.091 m respectively. Building extraction inclusive of roof top based on slope and contour analysis undertaken indicate the capability of the approach while single tree extraction through aspect analysis appears to preserve the accuracy of the extraction accordingly. The paper has evaluated the suitable methods of extracting non-ground features and the effective segmentation of the Li<span class="hlt">DAR</span> data.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2015SPIE.9669E..0GC&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2015SPIE.9669E..0GC&link_type=ABSTRACT"><span id="translatedtitle">Detection of fault structures with airborne Li<span class="hlt">DAR</span> point-cloud data</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Chen, Jie; Du, Lei</p> <p>2015-08-01</p> <p>The airborne Li<span class="hlt">DAR</span> (Light Detection And Ranging) technology is a new type of aerial earth observation method which can be used to produce high-precision DEM (Digital Elevation Model) quickly and reflect ground surface information directly. Fault structure is one of the key forms of crustal movement, and its quantitative description is the key to the research of crustal movement. The airborne Li<span class="hlt">DAR</span> point-cloud data is used to detect and extract fault structures automatically based on linear extension, elevation mutation and slope abnormal characteristics. Firstly, the Li<span class="hlt">DAR</span> point-cloud data is processed to filter out buildings, vegetation and other non-surface information with the TIN (Triangulated Irregular Network) filtering method and Burman model calibration method. TIN and DEM are made from the processed data sequentially. Secondly, linear fault structures are extracted based on dual-threshold method. Finally, high-precision DOM (Digital Orthophoto Map) and other geological knowledge are used to check the accuracy of fault structure extraction. An experiment is carried out in Beiya Village of Yunnan Province, China. With Li<span class="hlt">DAR</span> technology, results reveal that: the airborne Li<span class="hlt">DAR</span> point-cloud data can be utilized to extract linear fault structures accurately and automatically, measure information such as height, width and slope of fault structures with high precision, and detect faults in areas with vegetation coverage effectively.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012AGUFMNH31A1588K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012AGUFMNH31A1588K"><span id="translatedtitle">Study of Ground Subsidence in North West Houston using GPS, Li<span class="hlt">DAR</span> and InSAR techniques</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Karacay, A.; Khan, S. D.</p> <p>2012-12-01</p> <p>Land subsidence can be caused by natural or human activities, such as carbonate dissolution, extraction of material from mines, soil compaction and fluid withdrawal. This phenomenon affects many cities around the world, such as Nagoya-Japan, Venice-Italy, San Joaquin Valley and Long Beach in California. Recent work by Engelkemeir et <span class="hlt">al</span>, (2010), suggested that subsidence occurred as high as 5.6 cm/year in northwest Houston. The processes that may contribute to land subsidence in the Houston-Galveston area includes faulting, soil compaction, salt tectonic, water pumping and hydrocarbon extraction. This study aims to assess the possible role of water pumping on subsidence. Northwest Houston has two aquifer systems, the Evangeline and Chicot aquifers that dip in the southeast direction. The effect of water pumping on subsidence from these two aquifers was monitored using InSAR, GPS and Li<span class="hlt">DAR</span> data. The data from eleven GPS stations were processed using Online Positioning User Service (OPUS) of National Geodetic Survey (NGS). Three of these GPS stations are Continuously Operating Reference Stations (CORS) and eight are Port-A-Measure (PAM) sites. All the GPS data were obtained from Harris-Galveston Subsidence District (HGSD). CORS sites were used as reference stations for processing GPS data from the PAM stations. GPS data show that subsidence rate in northwest Houston decreased to approximately 2 cm/year. In addition, the surface deformation is also estimated using Light Detection and Ranging (Li<span class="hlt">DAR</span>) technique. For this purpose, raw Li<span class="hlt">DAR</span> (LAS-Long ASCII Standart) files of 2001 and 2008 were processed. The subsidence rate near the Hockley Fault was calculated by applying zonal statistics method on Li<span class="hlt">DAR</span> data which shows about 10 cm of subsidence in nine years. This result is supported by processed GPS data from PAM site 48 that show subsidence rate of 1.3 cm/yr. For the InSAR (Interferometric Synthetic Aperture Radar) technique, an image pair of PALSAR (The Phased Array</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2016JARS...10.6022W&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2016JARS...10.6022W&link_type=ABSTRACT"><span id="translatedtitle">Automatic extraction of building boundaries using aerial Li<span class="hlt">DAR</span> data</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Wang, Ruisheng; Hu, Yong; Wu, Huayi; Wang, Jian</p> <p>2016-01-01</p> <p>Building extraction is one of the main research topics of the photogrammetry community. This paper presents automatic algorithms for building boundary extractions from aerial Li<span class="hlt">DAR</span> data. First, segmenting height information generated from Li<span class="hlt">DAR</span> data, the outer boundaries of aboveground objects are expressed as closed chains of oriented edge pixels. Then, building boundaries are distinguished from nonbuilding ones by evaluating their shapes. The candidate building boundaries are reconstructed as rectangles or regular polygons by applying new algorithms, following the hypothesis verification paradigm. These algorithms include constrained searching in Hough space, enhanced Hough transformation, and the sequential linking technique. The experimental results show that the proposed algorithms successfully extract building boundaries at rates of 97%, 85%, and 92% for three Li<span class="hlt">DAR</span> datasets with varying scene complexities.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2009AGUFMIN33A1033G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2009AGUFMIN33A1033G"><span id="translatedtitle">Using 3D visual tools with Li<span class="hlt">DAR</span> for environmental outreach</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Glenn, N. F.; Mannel, S.; Ehinger, S.; Moore, C.</p> <p>2009-12-01</p> <p>The project objective is to develop visualizations using light detection and ranging (Li<span class="hlt">DAR</span>) data and other data sources to increase community understanding of remote sensing data for earth science. These data are visualized using Google Earth and other visualization methods. Final products are delivered to K-12, state, and federal agencies to share with their students and community constituents. Once our partner agencies were identified, we utilized a survey method to better understand their technological abilities and use of visualization products. The final multimedia products include a visualization of Li<span class="hlt">DAR</span> and well data for water quality mapping in a southeastern Idaho watershed; a tour of hydrologic points of interest in southeastern Idaho visited by thousands of people each year, and post-earthquake features near Borah Peak, Idaho. In addition to the customized multimedia materials, we developed tutorials to encourage our partners to utilize these tools with their own Li<span class="hlt">DAR</span> and other scientific data.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/26164889','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/26164889"><span id="translatedtitle">[Analysis of an Air Pollution Process Using Li<span class="hlt">DAR</span> in Nanjing, Spring of 2014].</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Bao, Qing; He, Jun-liang; Zha, Yong; Cheng, Feng; Li, Qian-nan</p> <p>2015-04-01</p> <p>Based on environmental monitoring data, meteorological data and the results of numerical simulation, a typical air pollution process in Nanjing, from 26th May to 1st June, 2014 was deeply analyzed combining aerosol extinction coefficient derived from Li<span class="hlt">DAR</span> system. Experimental results showed that the entire pollution process was affected by both local pollution and exogenous inputs including dust and smoke. Meteorological factors played a significant role in the generation and elimination of pollutants. Low pressure and temperature inversion also hindered the diffusion of pollutants, while strong rainfall terminated the pollution process. During the pollution, the height of atmospheric boundary layer was lower than normal situation and changed little during the pollution period, which provided a poor diffusion condition for pollutants. Li<span class="hlt">DAR</span> could accurately detect aerosol vertical structure which was able to capture the temporal and spatial variation of pollutant distributions. Therefore, Li<span class="hlt">DAR</span> can be of great significance for the atmospheric pollution monitoring. PMID:26164889</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2016JPRS..113...59S&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2016JPRS..113...59S&link_type=ABSTRACT"><span id="translatedtitle">Octree-based segmentation for terrestrial Li<span class="hlt">DAR</span> point cloud data in industrial applications</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Su, Yun-Ting; Bethel, James; Hu, Shuowen</p> <p>2016-03-01</p> <p>Automated and efficient algorithms to perform segmentation of terrestrial Li<span class="hlt">DAR</span> data is critical for exploitation of 3D point clouds, where the ultimate goal is CAD modeling of the segmented data. In this work, a novel segmentation technique is proposed, starting with octree decomposition to recursively divide the scene into octants or voxels, followed by a novel split and merge framework that uses graph theory and a series of connectivity analyses to intelligently merge components into larger connected components. The connectivity analysis, based on a combination of proximity, orientation, and curvature connectivity criteria, is designed for the segmentation of pipes, vessels, and walls from terrestrial Li<span class="hlt">DAR</span> data of piping systems at industrial sites, such as oil refineries, chemical plants, and steel mills. The proposed segmentation method is exercised on two terrestrial Li<span class="hlt">DAR</span> datasets of a steel mill and a chemical plant, demonstrating its ability to correctly reassemble and segregate features of interest.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013AGUFM.V53F..07B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013AGUFM.V53F..07B"><span id="translatedtitle">4D Micro-Piston Motion of Halemaumau Lava Lake Surface Measured with Ground-Based Tripod Li<span class="hlt">DAR</span>, Kilauea, Hawaii</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Bawden, G. W.; Patrick, M. R.; Orr, T. R.; Howle, J.; Bond, S.; Thelen, W. A.; Kauahikaua, J. P.; Angeli, K.; Pelkie, A.; Molnia, B. F.</p> <p>2013-12-01</p> <p>We measured decimeter-scale oscillations in the elevation of the Halemaumau lava lake (HLL) surface at Kilauea Volcano, Hawaii, during a sequence of ground-based Tripod-Li<span class="hlt">DAR</span> (T-Li<span class="hlt">DAR</span>) laser scans September 13-14, 2012. Geodetically measuring elevational changes of a dynamic lava lake surface has inherent risks and technical challenges, including the ability to see the lake surface through the volcanic gases. We successfully penetrated most of the dense volcanic gases from the rim of the HLL using the Optech LR laser scanner 1-micron (1064 nm) laser (a wavelength that is not attenuated by water) to measure elevation changes of the surface of the active lava lake 164 meters below the scanner. We found that the average elevation of the entire lava lake surface oscillated with an average 10-cm amplitude across the HLL with increased amplitude (2-3 times larger) proximal to the downwelling portion of the lake. A temporal power-spectrum analysis of the T-Li<span class="hlt">DAR</span> point cloud resolved an 8.4-second primary oscillation frequency with secondary frequencies at 3.3-second intervals from the primary (1.8, 5.1, 8.4, 11.7 seconds). Preliminary analysis of the seismic spectra shows a peak in the seismic signal at 7.8 seconds (0.13 hz) for the same time period. Qualitative assessment of time-lapse video of the lava lake surface visually confirms that the lava lake rises and falls about every 8 seconds with superimposed smaller-amplitude elevation changes approximately every 3 seconds. We suggest the term micro-pistoning to distinguish this behavior from the larger-scale gas pistoning events at Kilauea that take place over several minutes (Patrick, M. et <span class="hlt">al</span>, Bull Volcanol, V73(9)pp 1179-1186, 2011).</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/20182905','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/20182905"><span id="translatedtitle">Estimating stem volume and biomass of Pinus koraiensis using Li<span class="hlt">DAR</span> data.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Kwak, Doo-Ahn; Lee, Woo-Kyun; Cho, Hyun-Kook; Lee, Seung-Ho; Son, Yowhan; Kafatos, Menas; Kim, So-Ra</p> <p>2010-07-01</p> <p>The objective of this study was to estimate the stem volume and biomass of individual trees using the crown geometric volume (CGV), which was extracted from small-footprint light detection and ranging (Li<span class="hlt">DAR</span>) data. Attempts were made to analyze the stem volume and biomass of Korean Pine stands (Pinus koraiensis Sieb. et Zucc.) for three classes of tree density: low (240 N/ha), medium (370 N/ha), and high (1,340 N/ha). To delineate individual trees, extended maxima transformation and watershed segmentation of image processing methods were applied, as in one of our previous studies. As the next step, the crown base height (CBH) of individual trees has to be determined; information for this was found in the Li<span class="hlt">DAR</span> point cloud data using k-means clustering. The Li<span class="hlt">DAR</span>-derived CGV and stem volume can be estimated on the basis of the proportional relationship between the CGV and stem volume. As a result, low tree-density plots had the best performance for Li<span class="hlt">DAR</span>-derived CBH, CGV, and stem volume (R (2) = 0.67, 0.57, and 0.68, respectively) and accuracy was lowest for high tree-density plots (R (2) = 0.48, 0.36, and 0.44, respectively). In the case of medium tree-density plots accuracy was R (2) = 0.51, 0.52, and 0.62, respectively. The Li<span class="hlt">DAR</span>-derived stem biomass can be predicted from the stem volume using the wood basic density of coniferous trees (0.48 g/cm(3)), and the Li<span class="hlt">DAR</span>-derived above-ground biomass can then be estimated from the stem volume using the biomass conversion and expansion factors (BCEF, 1.29) proposed by the Korea Forest Research Institute (KFRI). PMID:20182905</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012AGUFMNH13A1598K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012AGUFMNH13A1598K"><span id="translatedtitle">Li<span class="hlt">DAR</span> data and SAR imagery acquired by an unmanned helicopter for rapid landslide investigation</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kasai, M.; Tanaka, Y.; Yamazaki, T.</p> <p>2012-12-01</p> <p>When earthquakes or heavy rainfall hits a landslide prone area, initial actions require estimation of the size of damage to people and infrastructure. This includes identifying the number and size of newly collapsed or expanded landslides, and appraising subsequent risks from remobilization of landslides and debris materials. In inapproachable areas, the UAV (Unmanned Aerial Vehicles) is likely to be of greatest use. In addition, repeat monitoring of sites after the event is a way of utilizing UAVs, particularly in terms of cost and convenience. In this study, Li<span class="hlt">DAR</span> (SkEyesBox MP-1) data and SAR (Nano SAR) imagery, acquired over 0.5 km2 landslide prone area, are presented to assess the practicability of using unmanned helicopters (in this case a 10 year old YAMAHA RMAX G1) in these situations. Li<span class="hlt">DAR</span> data was taken in July 2012, when tree foliage covered the ground surface. However, imagery was of sufficient quality to identify and measure landslide features. Nevertheless, Li<span class="hlt">DAR</span> data obtained by a manned helicopter in the same area in August 2008 was more detailed, reflecting the function of the Li<span class="hlt">DAR</span> scanner. On the other hand, 2 m resolution Nano SAR imagery produced reasonable results to elucidate hillslope condition. A quick method for data processing without loss of image quality was also investigated. In conclusion, the Li<span class="hlt">DAR</span> scanner and UAV employed here could be used to plan immediate remedial activity of the area, before Li<span class="hlt">DAR</span> measurement with a manned helicopter can be organized. SAR imagery from UAV is also available for this initial activity, and can be further applied to long term monitoring.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3189831','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3189831"><span id="translatedtitle">Reconstruction and analysis of a deciduous sapling using digital photographs or terrestrial-Li<span class="hlt">DAR</span> technology</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Delagrange, Sylvain; Rochon, Pascal</p> <p>2011-01-01</p> <p>Background and Aims To meet the increasing need for rapid and non-destructive extraction of canopy traits, two methods were used and compared with regard to their accuracy in estimatating 2-D and 3-D parameters of a hybrid poplar sapling. Methods The first method consisted of the analysis of high definition photographs in Tree Analyser (TA) software (PIAF-INRA/Kasetsart University). TA allowed the extraction of individual traits using a space carving approach. The second method utilized 3-D point clouds acquired from terrestrial light detection and ranging (T-Li<span class="hlt">DAR</span>) scans. T-Li<span class="hlt">DAR</span> scans were performed on trees without leaves to reconstruct the lignified structure of the sapling. From this skeleton, foliage was added using simple modelling rules extrapolated from field measurements. Validation of the estimated dimension and the accuracy of reconstruction was then achieved by comparison with an empirical data set. Key Results TA was found to be slightly less precise than T-Li<span class="hlt">DAR</span> for estimating tree height, canopy height and mean canopy diameter, but for 2-D traits both methods were, however, fully satisfactory. TA tended to over-estimate total leaf area (error up to 50 %), but better estimates were obtained by reducing the size of the voxels used for calculations. In contrast, T-Li<span class="hlt">DAR</span> estimated total leaf area with an error of <6 %. Finally, both methods led to an over-estimation of canopy volume. With respect to this trait, T-Li<span class="hlt">DAR</span> (14·5 % deviation) greatly surpassed the accuracy of TA (up to 50 % deviation), even if the voxels used were reduced in size. Conclusions Taking into account their magnitude of data acquisition and analysis and their accuracy in trait estimations, both methods showed contrasting potential future uses. Specifically, T-Li<span class="hlt">DAR</span> is a particularly promising tool for investigating the development of large perennial plants, by itself or in association with plant modelling. PMID:21515607</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/1054709','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/1054709"><span id="translatedtitle">Detailed Hydrographic Feature Extraction from High-Resolution Li<span class="hlt">DAR</span> Data</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Danny L. Anderson</p> <p>2012-05-01</p> <p>Detailed hydrographic feature extraction from high-resolution light detection and ranging (Li<span class="hlt">DAR</span>) data is investigated. Methods for quantitatively evaluating and comparing such extractions are presented, including the use of sinuosity and longitudinal root-mean-square-error (LRMSE). These metrics are then used to quantitatively compare stream networks in two studies. The first study examines the effect of raster cell size on watershed boundaries and stream networks delineated from Li<span class="hlt">DAR</span>-derived digital elevation models (DEMs). The study confirmed that, with the greatly increased resolution of Li<span class="hlt">DAR</span> data, smaller cell sizes generally yielded better stream network delineations, based on sinuosity and LRMSE. The second study demonstrates a new method of delineating a stream directly from Li<span class="hlt">DAR</span> point clouds, without the intermediate step of deriving a DEM. Direct use of Li<span class="hlt">DAR</span> point clouds could improve efficiency and accuracy of hydrographic feature extractions. The direct delineation method developed herein and termed “mDn”, is an extension of the D8 method that has been used for several decades with gridded raster data. The method divides the region around a starting point into sectors, using the Li<span class="hlt">DAR</span> data points within each sector to determine an average slope, and selecting the sector with the greatest downward slope to determine the direction of flow. An mDn delineation was compared with a traditional grid-based delineation, using TauDEM, and other readily available, common stream data sets. Although, the TauDEM delineation yielded a sinuosity that more closely matches the reference, the mDn delineation yielded a sinuosity that was higher than either the TauDEM method or the existing published stream delineations. Furthermore, stream delineation using the mDn method yielded the smallest LRMSE.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013AGUFM.B43C0522R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013AGUFM.B43C0522R"><span id="translatedtitle">Li<span class="hlt">DAR</span> remote sensing observations for forest assessment and recovery responses following disturbance</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Rosette, J.; Suárez, J.; Fonweben, J.; North, P.</p> <p>2013-12-01</p> <p>Li<span class="hlt">DAR</span> data covering 400 km2 in the Cowal and Trossacs Forest District, Scotland, U.K., were used to provide a low cost solution to update the database of public forests and to produce multi-scale cartographic products for supporting management decisions in the event of forest disturbance such as infestation or wind damage. All parameter estimates were directly obtained from the Li<span class="hlt">DAR</span> data without the necessity of field calibration. This was achieved using a hybrid approach integrating current stand models for Sitka spruce (Picea sitchensis bong. Carr) and Li<span class="hlt">DAR</span> analysis. More conventional field methods offer percentage sampling, permitting only a proportion of stands to be surveyed each year and aiming to represent stand-level conditions. The use of Li<span class="hlt">DAR</span> is advantageous in allowing a complete observation-based assessment throughout the forest and greatly-improved spatial representation of important forest parameters. Time-series analysis was performed using Li<span class="hlt">DAR</span> data collected in the past 10 years. This analysis allowed us to establish growth trajectories in the forest stands, automatically discriminating areas of growth, those whose growth had been affected by disease and the occurrence of windthrow gaps. The results were compared to the cartography produced by the Forest District after a severe wind storm that affected the area in 2012. This analysis showed the ability of Li<span class="hlt">DAR</span> to create a more precise location and extent of catastrophic damage and windthrow gaps. In addition, once windthrow has occurred, progression of further damage in existing canopy gaps can be observed. This approach additionally allows the impact of disease on forest growth and subsequent recovery response to be monitored.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/23913155','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/23913155"><span id="translatedtitle">Drug-to-antibody ratio (<span class="hlt">DAR</span>) and drug load distribution by LC-ESI-MS.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Basa, Louisette</p> <p>2013-01-01</p> <p>This chapter describes an LC-ESI-MS method for the <span class="hlt">DAR</span> and drug load distribution analysis that is suitable for lysine-linked ADCs. The ADC sample is desalted using a reversed-phase LC column with an acetonitrile gradient prior to online MS analysis. The MS spectrum is processed (deconvoluted) and converted to a series of zero charge state masses that corresponds to the increasing number of drugs in the ADC. Integration of the mass peak area allows the calculation of the <span class="hlt">DAR</span> and drug load distribution of ADCs. PMID:23913155</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2015APS..APR.S5006A&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2015APS..APR.S5006A&link_type=ABSTRACT"><span id="translatedtitle">Direct injection into the Iso<span class="hlt">DAR</span> Cyclotron using a RFQ</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Axani, Spencer; IsoDAR Collaboration</p> <p>2015-04-01</p> <p>Beginning in the 1970s, the use of Radio Frequency Quadrupoles (RFQs) has been pervasive in linear accelerators in order to accelerate, bunch, and separate ion species. Current research suggests this may be an ideal way to inject a low energy H2+ beam axially into a cyclotron. The Iso<span class="hlt">DAR</span> (Isotope Decay At Rest) experiment aims to implement this injection system in order to achieve higher Low Energy Beam Transport (LEBT) efficiencies and ultimately construct a novel compact neutrino factory to test the hypothesis of sterile neutrinos. This talk will focus on the research and development needed to implement a RFQ into the Iso<span class="hlt">DAR</span> experiment.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://medlineplus.gov/ency/article/002189.htm','NIH-MEDLINEPLUS'); return false;" href="https://medlineplus.gov/ency/article/002189.htm"><span id="translatedtitle"><span class="hlt">ALS</span> - resources</span></a></p> <p><a target="_blank" href="http://medlineplus.gov/">MedlinePlus</a></p> <p></p> <p></p> <p>Resources - <span class="hlt">ALS</span> ... The following organizations are good resources for information on amyotrophic lateral sclerosis : Muscular Dystrophy Association -- mda.org/disease/amyotrophic-lateral-sclerosis National Amyotrophic Lateral Sclerosis (<span class="hlt">ALS</span>) Registry -- ...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.alsa.org/','NIH-MEDLINEPLUS'); return false;" href="http://www.alsa.org/"><span id="translatedtitle"><span class="hlt">ALS</span> Association</span></a></p> <p><a target="_blank" href="http://medlineplus.gov/">MedlinePlus</a></p> <p></p> <p></p> <p>... <span class="hlt">ALS</span>. Find Out How Our Mission Leading the fight to treat and cure <span class="hlt">ALS</span> through global research ... you participate, advocate, and donate, you advance the fight to find the cure and lead us toward ...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013EGUGA..15.3366C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013EGUGA..15.3366C"><span id="translatedtitle">Climate change induced heat wave hazard in eastern Africa: <span class="hlt">Dar</span> Es Salaam (Tanzania) and Addis Ababa (Ethiopia) case study</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Capuano, Paolo; Sellerino, Mariangela; Di Ruocco, Angela; Kombe, Wilbard; Yeshitela, Kumelachew</p> <p>2013-04-01</p> <p>Last decades, new records were set in the world for tornadoes, drought, wind, floods, wildfires and hot temperatures, testifying unusual weather and climate patterns with increasing frequency and intensity of extreme weather events. Extreme heat events are natural hazards affecting many regions in the world, nevertheless limited work has been done on the analysis and effects of extreme heat events in Africa, that is considered a continent particularly vulnerable to the effects of climate change. In fact, the increase of temperature expected in the African continent during the 21st century is larger than the global mean warming, being about 3° to 4° C, about 1.5 times the global temperature increase (Christensen et <span class="hlt">al</span>., 2007; Gualdi et <span class="hlt">al</span>., 2012), with the subtropical regions projected to warm more than the tropical regions. Observations and downscaled model simulations (RCP4.5 and RCP8.5 IPCC scenarios) are analyzed to describe heat wave characteristics in <span class="hlt">Dar</span> es Salaam (Tanzania) and Addis Ababa (Ethiopia), spanning the last five decades as well as that projected for the 21st century. Observed data are daily maximum and minimum temperature collected in the period 1961-2011; downscaled model simulations span up to 2050. Heat waves are defined following a peak over threshold approach by statistical comparison to historical meteorological baselines (site dependent), using a fixed absolute threshold. Projected future warming in the <span class="hlt">Dar</span> es Salaam and Addis Ababa shows a further increase in the heat waves parameters. Heat wave duration and hot days number are strictly correlated showing that the temperature rise could generate not only an increase of heat waves number but mainly a longer average duration, that can strongly affect the resilience capacity of the population, particularly the elder people. In fact, the impacts of heat waves on the society are determined also by temporal duration (Stephenson, 2008), in addition to their frequency, in fact the capacity of</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_11");'>11</a></li> <li><a href="#" onclick='return showDiv("page_12");'>12</a></li> <li class="active"><span>13</span></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_13 --> <div id="page_14" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_12");'>12</a></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li class="active"><span>14</span></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="261"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2009AGUFMIN33A1034C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2009AGUFMIN33A1034C"><span id="translatedtitle">Visualization of High-Resolution Li<span class="hlt">DAR</span> Topography in Google Earth</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Crosby, C. J.; Nandigam, V.; Arrowsmith, R.; Blair, J. L.</p> <p>2009-12-01</p> <p>The growing availability of high-resolution Li<span class="hlt">DAR</span> (Light Detection And Ranging) topographic data has proven to be revolutionary for Earth science research. These data allow scientists to study the processes acting on the Earth’s surfaces at resolutions not previously possible yet essential for their appropriate representation. In addition to their utility for research, the data have also been recognized as powerful tools for communicating earth science concepts for education and outreach purposes. Unfortunately, the massive volume of data produced by Li<span class="hlt">DAR</span> mapping technology can be a barrier to their use. To facilitate access to these powerful data for research and educational purposes, we have been exploring the use of Keyhole Markup Language (KML) and Google Earth to deliver Li<span class="hlt">DAR</span>-derived visualizations. The OpenTopography Portal (http://www.opentopography.org/) is a National Science Foundation-funded facility designed to provide access to Earth science-oriented Li<span class="hlt">DAR</span> data. OpenTopography hosts a growing collection of Li<span class="hlt">DAR</span> data for a variety of geologic domains, including many of the active faults in the western United States. We have found that the wide spectrum of Li<span class="hlt">DAR</span> users have variable scientific applications, computing resources, and technical experience and thus require a data distribution system that provides various levels of access to the data. For users seeking a synoptic view of the data, and for education and outreach purposes, delivering full-resolution images derived from Li<span class="hlt">DAR</span> topography into the Google Earth virtual globe is powerful. The virtual globe environment provides a freely available and easily navigated viewer and enables quick integration of the Li<span class="hlt">DAR</span> visualizations with imagery, geographic layers, and other relevant data available in KML format. Through region-dependant network linked KML, OpenTopography currently delivers over 20 GB of Li<span class="hlt">DAR</span>-derived imagery to users via simple, easily downloaded KMZ files hosted at the Portal</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2008AGUFMIN41B1149C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2008AGUFMIN41B1149C"><span id="translatedtitle">KML-Based Access and Visualization of High Resolution Li<span class="hlt">DAR</span> Topography</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Crosby, C. J.; Blair, J. L.; Nandigam, V.; Memon, A.; Baru, C.; Arrowsmith, J. R.</p> <p>2008-12-01</p> <p>Over the past decade, there has been dramatic growth in the acquisition of Li<span class="hlt">DAR</span> (Light Detection And Ranging) high-resolution topographic data for earth science studies. Capable of providing digital elevation models (DEMs) more than an order of magnitude higher resolution than those currently available, Li<span class="hlt">DAR</span> data allow earth scientists to study the processes that contribute to landscape evolution at resolutions not previously possible yet essential for their appropriate representation. These datasets also have significant implications for earth science education and outreach because they provide an accurate representation of landforms and geologic hazards. Unfortunately, the massive volume of data produced by Li<span class="hlt">DAR</span> mapping technology can be a barrier to their use. To make these data available to a larger user community, we have been exploring the use of Keyhole Markup Language (KML) and Google Earth to provide access to Li<span class="hlt">DAR</span> data products and visualizations. Li<span class="hlt">DAR</span> digital elevation models are typically delivered in a tiled format that lends itself well to a KML-based distribution system. For Li<span class="hlt">DAR</span> datasets hosted in the GEON OpenTopography Portal (www.opentopography.org) we have developed KML files that show the extent of available Li<span class="hlt">DAR</span> DEMs and provide direct access to the data products. Users interact with these KML files to explore the extent of the available data and are able to select DEMs that correspond to their area of interest. Selection of a tile loads a download that the user can then save locally for analysis in their software of choice. The GEON topography system also has tools available that allow users to generate custom DEMs from Li<span class="hlt">DAR</span> point cloud data. This system is powerful because it enables users to access massive volumes of raw Li<span class="hlt">DAR</span> data and to produce DEM products that are optimized to their science applications. We have developed a web service that converts the custom DEM models produced by the system to a hillshade that is delivered to</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010AGUFM.B33A0385W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010AGUFM.B33A0385W"><span id="translatedtitle">Validating Li<span class="hlt">DAR</span> Derived Estimates of Canopy Height, Structure and Fractional Cover in Riparian Areas: A Comparison of Leaf-on and Leaf-off Li<span class="hlt">DAR</span> Data</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Wasser, L. A.; Chasmer, L. E.; Taylor, A.; Day, R.</p> <p>2010-12-01</p> <p>Characterization of riparian buffers is integral to understanding the landscape scale impacts of disturbance on wildlife and aquatic ecosystems. Riparian buffers may be characterized using in situ plot sampling or via high resolution remote sensing. Field measurements are time-consuming and may not cover a broad range of ecosystem types. Further, spectral remote sensing methods introduce a compromise between spatial resolution (grain) and area extent. Airborne Li<span class="hlt">DAR</span> can be used to continuously map and characterize riparian vegetation structure and composition due to the three-dimensional reflectance of laser pulses within and below the canopy, understory and at the ground surface. The distance between reflections (or ‘returns’) allows for detection of narrow buffer corridors at the landscape scale. There is a need to compare leaf-off and leaf-on surveyed Li<span class="hlt">DAR</span> data with in situ measurements to assess accuracy in landscape scale analysis. These comparisons are particularly important considering increased availability of leaf-off surveyed Li<span class="hlt">DAR</span> datasets. And given this increased availability, differences between leaf-on and leaf-off derived Li<span class="hlt">DAR</span> metrics are largely unknown for riparian vegetation of varying composition and structure. This study compares the effectiveness of leaf-on and leaf-off Li<span class="hlt">DAR</span> in characterizing riparian buffers of varying structure and composition as compared to field measurements. Field measurements were used to validate Li<span class="hlt">DAR</span> derived metrics. Vegetation height, canopy cover, density and overstory and understory species composition were recorded in 80 random plots of varying vegetation type, density and structure within a Pennsylvania watershed (-77.841, 40.818). Plot data were compared with Li<span class="hlt">DAR</span> data collected during leaf on and leaf off conditions to determine 1) accuracy of Li<span class="hlt">DAR</span> derived metrics compared to field measures and 2) differences between leaf-on and leaf-off Li<span class="hlt">DAR</span> metrics. Results illustrate that differences exist between</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013EGUGA..1512086C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013EGUGA..1512086C"><span id="translatedtitle">Urban morphological determinants of temperature regulating ecosystem services in African cities: the case of <span class="hlt">Dar</span> es Salaam, Tanzania</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Cavan, Gina; Lindley, Sarah; Kibassa, Deusdedit; Shemdoe, Riziki; Capuano, Paolo; De Paola, Francesco; Renner, Florian; Pauleit, Stephan</p> <p>2013-04-01</p> <p>Urban green structure provides important regulating ecosystem services, such as temperature and flood regulation, and thus, has the potential to increase the resilience of African cities to climate change. Green structures within urban areas are not only limited to discrete units associated with recreational parks, agricultural areas and open spaces: they also exist within zones which have other primary functions, such as church yards, along transport routes, and within residential areas. Differing characteristics of urban areas can be conceptualised and subsequently mapped through the idea of urban morphology types. Urban morphology types are classifications which combine facets of urban form and function. When mapped, UMT units provide biophysically relevant meso-scale geographical zones which can be used as the basis for understanding climate-related impacts and adaptations. For example, they support the assessment of urban temperature patterns and the temperature regulating services provided by urban green structures. There are some examples of the use of UMTs for assessing regulating ecosystem services in European cities but little similar knowledge is available in an African context. This paper outlines the concept of urban morphology types (UMTs) and how they were applied to African case study cities (Cavan et <span class="hlt">al</span>., 2012). It then presents the methods used to understand temperature regulating ecosystem services across an example African case study city, including (i) a GIS-based assessment of urban green structures, and (ii) applying an energy balance model to estimate current and future surface temperatures under climate change projections. The assessment is carried out for <span class="hlt">Dar</span> es Salaam, Tanzania. Existing evidence suggests increases in both mean and extreme temperatures in the city. Historical analysis of the number of hot days per year suggests a rise from a maximum of 47 days per year in the period 1961-87 to 72 days per year in 2003-2011 (Giugni et <span class="hlt">al</span></p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2013AGUFM.V43B2895A&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2013AGUFM.V43B2895A&link_type=ABSTRACT"><span id="translatedtitle">The Effect of Lava Texture on Li<span class="hlt">DAR</span> Attributes and Full Waveform</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Anderson, S. W.; Finnegan, D. C.; LeWinter, A.</p> <p>2013-12-01</p> <p>The distribution of glassy, vesicular, and crystalline textures on lava flow and dome surfaces provides insights regarding the physical and chemical processes occurring during emplacement. For silicic flows, these textures may reflect variations in the volatile content of lava upon eruption. To assess the efficacy of texture detection with our terrestrial full waveform Li<span class="hlt">DAR</span> system capable of measuring ~125,000 topographic points/second, we analyzed attribute and full waveform data from a variety of lava textures displayed on recent rhyolitic obsidian flows of the Inyo Dome chain (California) and pahoehoe and aa flows at Kilauea volcano (Hawaii). We find that attributes such as intensity, amplitude and deviation of the returned 1550nm laser pulse fall into discrete ranges associated with glassy, pumiceous and crystalline textures on both the rhyolitic and basaltic surfaces. This enables detection of vesicularity at ranges in excess of 500 m, making Li<span class="hlt">DAR</span> a useful tool for remotely determining lava texture. Scan times using our Riegl VZ1000 and VZ400 systems require only minutes, allowing for repeated scans over a short time period, and processing times are <1 hour. We have also analyzed the full digitized waveforms of Li<span class="hlt">DAR</span> pulses returned from these surfaces, and find that they also have unique signatures related to texture. We therefore suggest that Li<span class="hlt">DAR</span> can provide reliable information on lava texture during eruption, aiding in the interpretation of eruption hazards from increasing volatile contents.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3420181','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3420181"><span id="translatedtitle">Geospatial revolution and remote sensing Li<span class="hlt">DAR</span> in Mesoamerican archaeology</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Chase, Arlen F.; Fisher, Christopher T.; Leisz, Stephen J.; Weishampel, John F.</p> <p>2012-01-01</p> <p>The application of light detection and ranging (Li<span class="hlt">DAR</span>), a laser-based remote-sensing technology that is capable of penetrating overlying vegetation and forest canopies, is generating a fundamental shift in Mesoamerican archaeology and has the potential to transform research in forested areas world-wide. Much as radiocarbon dating that half a century ago moved archaeology forward by grounding archaeological remains in time, Li<span class="hlt">DAR</span> is proving to be a catalyst for an improved spatial understanding of the past. With Li<span class="hlt">DAR</span>, ancient societies can be contextualized within a fully defined landscape. Interpretations about the scale and organization of densely forested sites no longer are constrained by sample size, as they were when mapping required laborious on-ground survey. The ability to articulate ancient landscapes fully permits a better understanding of the complexity of ancient Mesoamerican urbanism and also aids in modern conservation efforts. The importance of this geospatial innovation is demonstrated with newly acquired Li<span class="hlt">DAR</span> data from the archaeological sites of Caracol, Cayo, Belize and Angamuco, Michoacán, Mexico. These data illustrate the potential of technology to act as a catalytic enabler of rapid transformational change in archaeological research and interpretation and also underscore the value of on-the-ground archaeological investigation in validating and contextualizing results. PMID:22802623</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://files.eric.ed.gov/fulltext/EJ1071342.pdf','ERIC'); return false;" href="http://files.eric.ed.gov/fulltext/EJ1071342.pdf"><span id="translatedtitle">Students' Experiences and Challenges of Blended Learning at the University of <span class="hlt">Dar</span> Es Salaam, Tanzania</span></a></p> <p><a target="_blank" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>Mtebe, Joel S.; Raphael, Christina</p> <p>2013-01-01</p> <p>Recent developments in Information and Communication Technologies (ICTs), especially eLearning, have heightened the need for University of <span class="hlt">Dar</span> es Salaam (UDSM) to supplement on-campus face-to-face delivery as well as meeting increased students' enrolments through blended distance learning. Since 2008, the University has been offering three…</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ars.usda.gov/research/publications/Publications.htm?seq_no_115=260894','TEKTRAN'); return false;" href="http://www.ars.usda.gov/research/publications/Publications.htm?seq_no_115=260894"><span id="translatedtitle">High-throughput genotyping of hop (Humulus lupulus L.) utilising diversity arrays technology (<span class="hlt">DAr</span>T)</span></a></p> <p><a target="_blank" href="http://www.ars.usda.gov/services/TekTran.htm">Technology Transfer Automated Retrieval System (TEKTRAN)</a></p> <p></p> <p></p> <p>Implementation of molecular methods in hop breeding is dependent on the availability of sizeable numbers of polymorphic markers and a comprehensive understanding of genetic variation. Diversity Arrays Technology (<span class="hlt">DAr</span>T) is a high-throughput cost-effective method for the discovery of large numbers of...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4861515','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4861515"><span id="translatedtitle">Clinical, Virologic, and Epidemiologic Characteristics of Dengue Outbreak, <span class="hlt">Dar</span> es Salaam, Tanzania, 2014</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Mboera, Leonard E.G.; De Nardo, Pasquale; Oriyo, Ndekya M.; Meschi, Silvia; Rumisha, Susan F.; Colavita, Francesca; Mhina, Athanas; Carletti, Fabrizio; Mwakapeje, Elibariki; Capobianchi, Maria Rosaria; Castilletti, Concetta; Di Caro, Antonino; Nicastri, Emanuele; Malecela, Mwelecele N.; Ippolito, Giuseppe</p> <p>2016-01-01</p> <p>We investigated a dengue outbreak in <span class="hlt">Dar</span> es Salaam, Tanzania, in 2014, that was caused by dengue virus (DENV) serotype 2. DENV infection was present in 101 (20.9%) of 483 patients. Patient age and location of residence were associated with infection. Seven (4.0%) of 176 patients were co-infected with malaria and DENV. PMID:27088845</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/22802623','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/22802623"><span id="translatedtitle">Geospatial revolution and remote sensing Li<span class="hlt">DAR</span> in Mesoamerican archaeology.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Chase, Arlen F; Chase, Diane Z; Fisher, Christopher T; Leisz, Stephen J; Weishampel, John F</p> <p>2012-08-01</p> <p>The application of light detection and ranging (Li<span class="hlt">DAR</span>), a laser-based remote-sensing technology that is capable of penetrating overlying vegetation and forest canopies, is generating a fundamental shift in Mesoamerican archaeology and has the potential to transform research in forested areas world-wide. Much as radiocarbon dating that half a century ago moved archaeology forward by grounding archaeological remains in time, Li<span class="hlt">DAR</span> is proving to be a catalyst for an improved spatial understanding of the past. With Li<span class="hlt">DAR</span>, ancient societies can be contextualized within a fully defined landscape. Interpretations about the scale and organization of densely forested sites no longer are constrained by sample size, as they were when mapping required laborious on-ground survey. The ability to articulate ancient landscapes fully permits a better understanding of the complexity of ancient Mesoamerican urbanism and also aids in modern conservation efforts. The importance of this geospatial innovation is demonstrated with newly acquired Li<span class="hlt">DAR</span> data from the archaeological sites of Caracol, Cayo, Belize and Angamuco, Michoacán, Mexico. These data illustrate the potential of technology to act as a catalytic enabler of rapid transformational change in archaeological research and interpretation and also underscore the value of on-the-ground archaeological investigation in validating and contextualizing results. PMID:22802623</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4377920','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4377920"><span id="translatedtitle">Pit Latrine Emptying Behavior and Demand for Sanitation Services in <span class="hlt">Dar</span> Es Salaam, Tanzania</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Jenkins, Marion W.; Cumming, Oliver; Cairncross, Sandy</p> <p>2015-01-01</p> <p>Pit latrines are the main form of sanitation in unplanned areas in many rapidly growing developing cities. Understanding demand for pit latrine fecal sludge management (FSM) services in these communities is important for designing demand-responsive sanitation services and policies to improve public health. We examine latrine emptying knowledge, attitudes, behavior, trends and rates of safe/unsafe emptying, and measure demand for a new hygienic latrine emptying service in unplanned communities in <span class="hlt">Dar</span> Es Salaam (<span class="hlt">Dar</span>), Tanzania, using data from a cross-sectional survey at 662 residential properties in 35 unplanned sub-wards across <span class="hlt">Dar</span>, where 97% had pit latrines. A picture emerges of expensive and poor FSM service options for latrine owners, resulting in widespread fecal sludge exposure that is likely to increase unless addressed. Households delay emptying as long as possible, use full pits beyond what is safe, face high costs even for unhygienic emptying, and resort to unsafe practices like ‘flooding out’. We measured strong interest in and willingness to pay (WTP) for the new pit emptying service at 96% of residences; 57% were WTP ≥U.S. $17 to remove ≥200 L of sludge. Emerging policy recommendations for safe FSM in unplanned urban communities in <span class="hlt">Dar</span> and elsewhere are discussed. PMID:25734790</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2009NHESS...9..935L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2009NHESS...9..935L"><span id="translatedtitle">Engineering monitoring of rockfall hazards along transportation corridors: using mobile terrestrial Li<span class="hlt">DAR</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Lato, M.; Hutchinson, J.; Diederichs, M.; Ball, D.; Harrap, R.</p> <p>2009-06-01</p> <p>Geotechnical hazards along linear transportation corridors are challenging to identify and often require constant monitoring. Inspecting corridors using traditional, manual methods requires the engineer to be unnecessarily exposed to the hazard. It also requires closure of the corridor to ensure safety of the worker from passing vehicles. This paper identifies the use of mobile terrestrial Li<span class="hlt">DAR</span> data as a compliment to traditional field methods. Mobile terrestrial Li<span class="hlt">DAR</span> is an emerging remote data collection technique capable of generating accurate fully three-dimensional virtual models while driving at speeds up to 100 km/h. Data is collected from a truck that causes no delays to active traffic nor does it impede corridor use. These resultant georeferenced data can be used for geomechanical structural feature identification and kinematic analysis, rockfall path identification and differential monitoring of rock movement or failure over time. Comparisons between mobile terrestrial and static Li<span class="hlt">DAR</span> data collection and analysis are presented. As well, detailed discussions on workflow procedures for possible implementation are discussed. Future use of mobile terrestrial Li<span class="hlt">DAR</span> data for corridor analysis will focus on repeated surveys and developing dynamic four-dimensional models, higher resolution data collection. As well, computationally advanced, spatially accurate, geomechanically controlled three-dimensional rockfall simulations should be investigated.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/18488621','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/18488621"><span id="translatedtitle">Hyperspectral and Li<span class="hlt">DAR</span> remote sensing of fire fuels in Hawaii Volcanoes National Park.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Varga, Timothy A; Asner, Gregory P</p> <p>2008-04-01</p> <p>Alien invasive grasses threaten to transform Hawaiian ecosystems through the alteration of ecosystem dynamics, especially the creation or intensification of a fire cycle. Across sub-montane ecosystems of Hawaii Volcanoes National Park on Hawaii Island, we quantified fine fuels and fire spread potential of invasive grasses using a combination of airborne hyperspectral and light detection and ranging (Li<span class="hlt">DAR</span>) measurements. Across a gradient from forest to savanna to shrubland, automated mixture analysis of hyperspectral data provided spatially explicit fractional cover estimates of photosynthetic vegetation, non-photosynthetic vegetation, and bare substrate and shade. Small-footprint Li<span class="hlt">DAR</span> provided measurements of vegetation height along this gradient of ecosystems. Through the fusion of hyperspectral and Li<span class="hlt">DAR</span> data, a new fire fuel index (FFI) was developed to model the three-dimensional volume of grass fuels. Regionally, savanna ecosystems had the highest volumes of fire fuels, averaging 20% across the ecosystem and frequently filling all of the three-dimensional space represented by each image pixel. The forest and shrubland ecosystems had lower FFI values, averaging 4.4% and 8.4%, respectively. The results indicate that the fusion of hyperspectral and Li<span class="hlt">DAR</span> remote sensing can provide unique information on the three-dimensional properties of ecosystems, their flammability, and the potential for fire spread. PMID:18488621</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/27088845','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/27088845"><span id="translatedtitle">Clinical, Virologic, and Epidemiologic Characteristics of Dengue Outbreak, <span class="hlt">Dar</span> es Salaam, Tanzania, 2014.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Vairo, Francesco; Mboera, Leonard E G; De Nardo, Pasquale; Oriyo, Ndekya M; Meschi, Silvia; Rumisha, Susan F; Colavita, Francesca; Mhina, Athanas; Carletti, Fabrizio; Mwakapeje, Elibariki; Capobianchi, Maria Rosaria; Castilletti, Concetta; Di Caro, Antonino; Nicastri, Emanuele; Malecela, Mwelecele N; Ippolito, Giuseppe</p> <p>2016-05-01</p> <p>We investigated a dengue outbreak in <span class="hlt">Dar</span> es Salaam, Tanzania, in 2014, that was caused by dengue virus (DENV) serotype 2. DENV infection was present in 101 (20.9%) of 483 patients. Patient age and location of residence were associated with infection. Seven (4.0%) of 176 patients were co-infected with malaria and DENV. PMID:27088845</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/25837107','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/25837107"><span id="translatedtitle">Registration of optical imagery and Li<span class="hlt">DAR</span> data using an inherent geometrical constraint.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Zhang, Wuming; Zhao, Jing; Chen, Mei; Chen, Yiming; Yan, Kai; Li, Linyuan; Qi, Jianbo; Wang, Xiaoyan; Luo, Jinghui; Chu, Qing</p> <p>2015-03-23</p> <p>A novel method for registering imagery with Light Detection And Ranging (Li<span class="hlt">DAR</span>) data is proposed. It is based on the phenomenon that the back-projection of Li<span class="hlt">DAR</span> point cloud of an object should be located within the object boundary in the image. Using this inherent geometrical constraint, the registration parameters computation of both data sets only requires Li<span class="hlt">DAR</span> point clouds of several objects and their corresponding boundaries in the image. The proposed registration method comprises of four steps: point clouds extraction, boundary extraction, back-projection computation and registration parameters computation. There are not any limitations on the geometrical and spectral properties of the object. So it is suitable not only for structured scenes with man-made objects but also for natural scenes. Moreover, the proposed method based on the inherent geometrical constraint can register two data sets derived from different parts of an object. It can be used to co-register TLS (Terrestrial Laser Scanning) Li<span class="hlt">DAR</span> point cloud and UAV (Unmanned aerial vehicle) image, which are obtaining more attention in the forest survey application. Using initial registration parameters comparable to POS (position and orientation system) accuracy, the performed experiments validated the feasibility of the proposed registration method. PMID:25837107</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014AGUFM.C32A..06H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014AGUFM.C32A..06H"><span id="translatedtitle">Using regional-scale Li<span class="hlt">DAR</span> surveys to validate operational snow models</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Hedrick, A. R.; Marshall, H. P.; Winstral, A. H.; Elder, K.; Yueh, S. H.; Cline, D. W.</p> <p>2014-12-01</p> <p>As survey costs continue to plummet and storage capabilities soar, large-scale multitemporal airborne Light Detection and Ranging (Li<span class="hlt">DAR</span>) surveys for high-resolution snow depth measurements are becoming commonplace in mountain research watersheds. Though there are disadvantages to the technique (e.g. poor temporal representation and high uncertainty in steep terrain and dense vegetation), the wealth of information with regard to previously unknown spatial snow depth distributions can be an valuable tool for assessing spatially distributed operational snow models. As a portion of NASA's second Cold Lands Processes Experiment (CLPX-2), two 750-km2 Li<span class="hlt">DAR</span> surveys were conducted over Northern Colorado in December and February of the 2006/2007 winter season. The resulting 5-m gridded changes in snow depth overlay 980 individual pixels of the SNOw Data Assimilation System (SNODAS) spatial framework. As an important operational snow model developed by NOAA's National Operational Hydrologic Remote Sensing Center (NOHRSC), SNODAS generally lacks independent validation datasets due to the data assimilation step critical for adjusting the energy balance and downscaled Numerical Weather Prediction (NWP) model components. The influence of sub-grid variability on SNODAS performance is assessed using the independent high resolution CLPX-2 Li<span class="hlt">DAR</span> changes in snow depth. This method provides a foundation for further studies to quantitatively address the affect of small-scale physiographic variables on various large-scale operational snow models by making use of forthcoming large-scale Li<span class="hlt">DAR</span> datasets.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://eric.ed.gov/?q=urban+AND+agriculture&pg=3&id=EJ509044','ERIC'); return false;" href="http://eric.ed.gov/?q=urban+AND+agriculture&pg=3&id=EJ509044"><span id="translatedtitle">Child Labour in Urban Agriculture: The Case of <span class="hlt">Dar</span> es Salaam, Tanzania.</span></a></p> <p><a target="_blank" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>Mlozi, Malongo R. S.</p> <p>1995-01-01</p> <p>Urban agriculture in <span class="hlt">Dar</span> es Salaam was found to use child labor of both children with parents of higher and lower socioeconomic status (SES). Discusses policy implications and calls for the education of parents of lower SES not to expect an economic contribution from their children's labor, and the education of children about their rights. (LZ)</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2014ISPAr.XL2..225S&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2014ISPAr.XL2..225S&link_type=ABSTRACT"><span id="translatedtitle">a Data Driven Method for Building Reconstruction from Li<span class="hlt">DAR</span> Point Clouds</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Sajadian, M.; Arefi, H.</p> <p>2014-10-01</p> <p>Airborne laser scanning, commonly referred to as Li<span class="hlt">DAR</span>, is a superior technology for three-dimensional data acquisition from Earth's surface with high speed and density. Building reconstruction is one of the main applications of Li<span class="hlt">DAR</span> system which is considered in this study. For a 3D reconstruction of the buildings, the buildings points should be first separated from the other points such as; ground and vegetation. In this paper, a multi-agent strategy has been proposed for simultaneous extraction and segmentation of buildings from Li<span class="hlt">DAR</span> point clouds. Height values, number of returned pulse, length of triangles, direction of normal vectors, and area are five criteria which have been utilized in this step. Next, the building edge points are detected using a new method named "Grid Erosion". A RANSAC based technique has been employed for edge line extraction. Regularization constraints are performed to achieve the final lines. Finally, by modelling of the roofs and walls, 3D building model is reconstructed. The results indicate that the proposed method could successfully extract the building from Li<span class="hlt">DAR</span> data and generate the building models automatically. A qualitative and quantitative assessment of the proposed method is then provided.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ars.usda.gov/research/publications/Publications.htm?seq_no_115=271443','TEKTRAN'); return false;" href="http://www.ars.usda.gov/research/publications/Publications.htm?seq_no_115=271443"><span id="translatedtitle">A comparison of two open source Li<span class="hlt">DAR</span> surface classification algorithms</span></a></p> <p><a target="_blank" href="http://www.ars.usda.gov/services/TekTran.htm">Technology Transfer Automated Retrieval System (TEKTRAN)</a></p> <p></p> <p></p> <p>With the progression of Li<span class="hlt">DAR</span> (Light Detection and Ranging) towards a mainstream resource management tool, it has become necessary to understand how best to process and analyze the data. While most ground surface identification algorithms remain proprietary and have high purchase costs; a few are op...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2016E%26ES...37a2068H&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2016E%26ES...37a2068H&link_type=ABSTRACT"><span id="translatedtitle">Mapping of post-event earthquake induced landslides in Sg. Mesilou using Li<span class="hlt">DAR</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Hanan Mat Yusoff, Habibah; Azahari Razak, Khamarrul; Yuen, Florence; Harun, Afifi; Talib, Jasmi; Mohamad, Zakaria; Ramli, Zamri; Abd Razab, Razain</p> <p>2016-06-01</p> <p>Earthquake is a common natural disaster in active tectonic regions. The disaster can induce cascading disasters such as debris flow, mudflow and reactivated old landslides. M 6.0 Ranau earthquake dated on June 05, 2015 coupling with intense and prolonged rainfall caused several mass movements such as debris flow, deep-seated and shallow landslides in Mesilou, Sabah. This study aims at providing a better insight into the use of advanced Li<span class="hlt">DAR</span> mapping technology for recognizing landslide induced by earthquakes particularly in a vegetated terrain, assessing post event hazard and analyzing its distribution for hazard zonation. We developed the landslide inventory using Li<span class="hlt">DAR</span>-derived visual analysis method and validated in the field. A landslide inventory map improved with the support of Li<span class="hlt">DAR</span> derivative data. Finally, landslide inventory was analysed by emphasizing its distribution and density in such a way that it provides clues of risky zone as a result of debris flow. We recommend that mitigation action and risk reduction should be taken place at a transport zone of the channel compared to other zones. This study indicates that modern airborne Li<span class="hlt">DAR</span> can be a good complementary tool for improving landslide inventory in a complex environment, and an effective tool for rapid regional hazard and risk assessment in the tropics.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_12");'>12</a></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li class="active"><span>14</span></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_14 --> <div id="page_15" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li class="active"><span>15</span></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="281"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2004AGUFM.G13B0812S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2004AGUFM.G13B0812S"><span id="translatedtitle">Spatially-aware Processing of Large Raw Li<span class="hlt">DAR</span> Data Sets</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Strane, M. D.; Oskin, M.</p> <p>2004-12-01</p> <p>An ultimate goal of Li<span class="hlt">DAR</span> (LIght Detection And Ranging) data acquisition is to produce a regularly sampled accurate topographic view of the surface of the Earth. Last-return and inverse-distance weighted sampling of raw Li<span class="hlt">DAR</span> data do not take into account the non-random distribution of raw data points. While elevation data produced by these methods is of high accuracy, gradients are not well-resolved and aliasing artifacts are produced, especially on low gradient surfaces. Because of the volume of data involved, resampling schemes that take into account the spatial distribution of raw data have been cumbersome to implement. We have developed a resampling method that uses the free open-source PostgresSQL database to store the raw Li<span class="hlt">DAR</span> data indexed spatially and as its original time series. This database permits rapid access to raw data points via spatial queries. A robust and expedient algorithm has been implemented to produce regularly gridded resampled data with a least squares plane fit regression. This algorithm reduces aliasing artifacts on low gradient surfaces. The algorithm is also a proof-of-concept to show that complex spatially-aware processing of large Li<span class="hlt">DAR</span> data sets is feasible on a reasonable time scale, and will be the basis for further improvements such as vegetation removal.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/25734790','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/25734790"><span id="translatedtitle">Pit latrine emptying behavior and demand for sanitation services in <span class="hlt">Dar</span> Es Salaam, Tanzania.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Jenkins, Marion W; Cumming, Oliver; Cairncross, Sandy</p> <p>2015-03-01</p> <p>Pit latrines are the main form of sanitation in unplanned areas in many rapidly growing developing cities. Understanding demand for pit latrine fecal sludge management (FSM) services in these communities is important for designing demand-responsive sanitation services and policies to improve public health. We examine latrine emptying knowledge, attitudes, behavior, trends and rates of safe/unsafe emptying, and measure demand for a new hygienic latrine emptying service in unplanned communities in <span class="hlt">Dar</span> Es Salaam (<span class="hlt">Dar</span>), Tanzania, using data from a cross-sectional survey at 662 residential properties in 35 unplanned sub-wards across <span class="hlt">Dar</span>, where 97% had pit latrines. A picture emerges of expensive and poor FSM service options for latrine owners, resulting in widespread fecal sludge exposure that is likely to increase unless addressed. Households delay emptying as long as possible, use full pits beyond what is safe, face high costs even for unhygienic emptying, and resort to unsafe practices like 'flooding out'. We measured strong interest in and willingness to pay (WTP) for the new pit emptying service at 96% of residences; 57% were WTP≥U.S. $17 to remove ≥200 L of sludge. Emerging policy recommendations for safe FSM in unplanned urban communities in <span class="hlt">Dar</span> and elsewhere are discussed. PMID:25734790</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2015AGUFM.B43C0560J&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2015AGUFM.B43C0560J&link_type=ABSTRACT"><span id="translatedtitle">Spatial Patterns of Trees from Airborne Li<span class="hlt">DAR</span> Using a Simple Tree Segmentation Algorithm</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Jeronimo, S.; Kane, V. R.; McGaughey, R. J.; Franklin, J. F.</p> <p>2015-12-01</p> <p>Objectives for management of forest ecosystems on public land incorporate a focus on maintenance and restoration of ecological functions through silvicultural manipulation of forest structure. The spatial pattern of residual trees - the horizontal element of structure - is a key component of ecological restoration prescriptions. We tested the ability of a simple Li<span class="hlt">DAR</span> individual tree segmentation method - the watershed transform - to generate spatial pattern metrics similar to those obtained by the traditional method - ground-based stem mapping - on forested plots representing the structural diversity of a large wilderness area (Yosemite NP) and a large managed area (Sierra NF) in the Sierra Nevada, Calif. Most understory and intermediate-canopy trees were not detected by the Li<span class="hlt">DAR</span> segmentation; however, Li<span class="hlt">DAR</span>- and field-based assessments of spatial pattern in terms of tree clump size distributions largely agreed. This suggests that (1) even when individual tree segmentation is not effective for tree density estimates, it can provide a good measurement of tree spatial pattern, and (2) a simple segmentation method is adequate to measure spatial pattern of large areas with a diversity of structural characteristics. These results lay the groundwork for a Li<span class="hlt">DAR</span> tool to assess clumping patterns across forest landscapes in support of restoration silviculture. This tool could describe spatial patterns of functionally intact reference ecosystems, measure departure from reference targets in treatment areas, and, with successive acquisitions, monitor treatment efficacy.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2014EGUGA..1612562T&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2014EGUGA..1612562T&link_type=ABSTRACT"><span id="translatedtitle">Airborne hyperspectral and Li<span class="hlt">DAR</span> data integration for weed detection</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Tamás, János; Lehoczky, Éva; Fehér, János; Fórián, Tünde; Nagy, Attila; Bozsik, Éva; Gálya, Bernadett; Riczu, Péter</p> <p>2014-05-01</p> <p>Agriculture uses 70% of global available fresh water. However, ca. 50-70% of water used by cultivated plants, the rest of water transpirated by the weeds. Thus, to define the distribution of weeds is very important in precision agriculture and horticulture as well. To survey weeds on larger fields by traditional methods is often time consuming. Remote sensing instruments are useful to detect weeds in larger area. In our investigation a 3D airborne laser scanner (RIEGL LMS-Q680i) was used in agricultural field near Sopron to scouting weeds. Beside the airborne Li<span class="hlt">DAR</span>, hyperspectral imaging system (AISA DUAL) and air photos helped to investigate weed coverage. The Li<span class="hlt">DAR</span> survey was carried out at early April, 2012, before sprouting of cultivated plants. Thus, there could be detected emerging of weeds and direction of cultivation. However airborne Li<span class="hlt">DAR</span> system was ideal to detect weeds, identification of weeds at species level was infeasible. Higher point density Li<span class="hlt">DAR</span> - Terrestrial laser scanning - systems are appropriate to distinguish weed species. Based on the results, laser scanner is an effective tool to scouting of weeds. Appropriate weed detection and mapping systems could contribute to elaborate water and herbicide saving management technique. This publication was supported by the OTKA project K 105789.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ars.usda.gov/research/publications/Publications.htm?seq_no_115=231779','TEKTRAN'); return false;" href="http://www.ars.usda.gov/research/publications/Publications.htm?seq_no_115=231779"><span id="translatedtitle">Biomass estimation of Douglas fir stands using airborne Li<span class="hlt">DAR</span> data</span></a></p> <p><a target="_blank" href="http://www.ars.usda.gov/services/TekTran.htm">Technology Transfer Automated Retrieval System (TEKTRAN)</a></p> <p></p> <p></p> <p>Biomass is an important parameter not only for carbon cycle modeling, but also for supporting land management operations (e.g. land use policy, forest fire management). Various remote sensing data have been utilized for biomass estimation, especially in forested areas. Li<span class="hlt">DAR</span> (Light Detection And Ran...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ars.usda.gov/research/publications/Publications.htm?seq_no_115=255950','TEKTRAN'); return false;" href="http://www.ars.usda.gov/research/publications/Publications.htm?seq_no_115=255950"><span id="translatedtitle">Errors in Li<span class="hlt">DAR</span>-derived shrub height and crown area on sloped terrain</span></a></p> <p><a target="_blank" href="http://www.ars.usda.gov/services/TekTran.htm">Technology Transfer Automated Retrieval System (TEKTRAN)</a></p> <p></p> <p></p> <p>This study developed and tested four methodologies for determining shrub height measurements with Li<span class="hlt">DAR</span> data in a semiarid shrub-steppe in southwestern Idaho, USA. Unique to this study was the focus of sagebrush height measurements on sloped terrain. The study also developed one of the first metho...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://eric.ed.gov/?q=social+AND+responsibility+AND+economic+AND+performance&pg=2&id=EJ953006','ERIC'); return false;" href="http://eric.ed.gov/?q=social+AND+responsibility+AND+economic+AND+performance&pg=2&id=EJ953006"><span id="translatedtitle">Integrating ICT into Teaching and Learning at the University of <span class="hlt">Dar</span> es Salaam</span></a></p> <p><a target="_blank" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>Mtebe, Joel S.; Dachi, Hilary; Raphael, Christina</p> <p>2011-01-01</p> <p>Since 1985, Tanzania has been undergoing significant political and economic changes from a centralized to a more market-oriented and globally connected economy. The University of <span class="hlt">Dar</span> es Salaam (UDSM) has responded to these changes by reviewing its legal status, vision, and functions, particularly those related to research, teaching, and public…</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/21243330','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/21243330"><span id="translatedtitle">High-throughput genotyping of hop (Humulus lupulus L.) utilising diversity arrays technology (<span class="hlt">DAr</span>T).</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Howard, E L; Whittock, S P; Jakše, J; Carling, J; Matthews, P D; Probasco, G; Henning, J A; Darby, P; Cerenak, A; Javornik, B; Kilian, A; Koutoulis, A</p> <p>2011-05-01</p> <p>Implementation of molecular methods in hop (Humulus lupulus L.) breeding is dependent on the availability of sizeable numbers of polymorphic markers and a comprehensive understanding of genetic variation. However, use of molecular marker technology is limited due to expense, time inefficiency, laborious methodology and dependence on DNA sequence information. Diversity arrays technology (<span class="hlt">DAr</span>T) is a high-throughput cost-effective method for the discovery of large numbers of quality polymorphic markers without reliance on DNA sequence information. This study is the first to utilise <span class="hlt">DAr</span>T for hop genotyping, identifying 730 polymorphic markers from 92 hop accessions. The marker quality was high and similar to the quality of <span class="hlt">DAr</span>T markers previously generated for other species; although percentage polymorphism and polymorphism information content (PIC) were lower than in previous studies deploying other marker systems in hop. Genetic relationships in hop illustrated by <span class="hlt">DAr</span>T in this study coincide with knowledge generated using alternate methods. Several statistical analyses separated the hop accessions into genetically differentiated North American and European groupings, with hybrids between the two groups clearly distinguishable. Levels of genetic diversity were similar in the North American and European groups, but higher in the hybrid group. The markers produced from this time and cost-efficient genotyping tool will be a valuable resource for numerous applications in hop breeding and genetics studies, such as mapping, marker-assisted selection, genetic identity testing, guidance in the maintenance of genetic diversity and the directed breeding of superior cultivars. PMID:21243330</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ars.usda.gov/research/publications/Publications.htm?seq_no_115=288819','TEKTRAN'); return false;" href="http://www.ars.usda.gov/research/publications/Publications.htm?seq_no_115=288819"><span id="translatedtitle">Diversity Arrays Technology (<span class="hlt">DAr</span>T) platform for genotyping and mapping in carrot (Daucus carota L.)</span></a></p> <p><a target="_blank" href="http://www.ars.usda.gov/services/TekTran.htm">Technology Transfer Automated Retrieval System (TEKTRAN)</a></p> <p></p> <p></p> <p>Carrot is one of the most important root vegetable crops grown worldwide on more than one million hectares. Its progenitor, wild Daucus carota, is a weed commonly occurring across continents in the temperate climatic zone. Diversity Array Technology (<span class="hlt">DAr</span>T) is a microarray-based molecular marker syst...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://eric.ed.gov/?q=genetics&pg=2&id=EJ936928','ERIC'); return false;" href="http://eric.ed.gov/?q=genetics&pg=2&id=EJ936928"><span id="translatedtitle">Genetics and Human Agency: Comment on <span class="hlt">Dar</span>-Nimrod and Heine (2011)</span></a></p> <p><a target="_blank" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>Turkheimer, Eric</p> <p>2011-01-01</p> <p><span class="hlt">Dar</span>-Nimrod and Heine (2011) decried genetic essentialism without denying the importance of genetics in the genesis of human behavior, and although I agree on both counts, a deeper issue remains unaddressed: how should we adjust our cognitions about our own behavior in light of genetic influence, or is it perhaps not necessary to take genetics into…</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://files.eric.ed.gov/fulltext/ED535262.pdf','ERIC'); return false;" href="http://files.eric.ed.gov/fulltext/ED535262.pdf"><span id="translatedtitle">An Analysis of Student Reading as Measured on the Diagnostic Assessment of Reading (<span class="hlt">DAR</span>)</span></a></p> <p><a target="_blank" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>Baca, Jo-Ann M.; Shepperson, Barbara A.</p> <p>2006-01-01</p> <p>As part of the reporting of Delaware's State Improvement Grant (DelaSIG), the Delaware Education Research and Development Center (R&D Center) completed a study on the Diagnostic Assessment of Reading (<span class="hlt">DAR</span>) scores of students whose teachers attended a professional development program designed to help focus teacher instruction of struggling readers…</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://eric.ed.gov/?q=social+AND+genetics&id=EJ936968','ERIC'); return false;" href="http://eric.ed.gov/?q=social+AND+genetics&id=EJ936968"><span id="translatedtitle">Genetic Essentialism, Neuroessentialism, and Stigma: Commentary on <span class="hlt">Dar</span>-Nimrod and Heine (2011)</span></a></p> <p><a target="_blank" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>Haslam, Nick</p> <p>2011-01-01</p> <p><span class="hlt">Dar</span>-Nimrod and Heine (2011) presented a masterfully broad review of the implications of genetic essentialism for understandings of human diversity. This commentary clarifies the reasons that essentialist thinking has problematic social consequences and links genetic forms of essentialism to those invoking neural essences. The mounting evidence…</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014EGUGA..16.5939T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014EGUGA..16.5939T"><span id="translatedtitle">Erosion in vineyards and Li<span class="hlt">DAR</span>: new opportunities for anthropogenic terraced landscapes</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Tarolli, Paolo; Sofia, Giulia; Calligaro, Simone; Prosdocimi, Massimo; Preti, Federico; Dalla Fontana, Giancarlo</p> <p>2014-05-01</p> <p>Vineyard landscapes are a relevant part of the European cultivated land, and several authors concluded that they are the agricultural practice that causes the highest soil loss. Since grape quality depends on the availability of water for the vineyards, and since soil erosion is an important parameter dictating the sustainability of vineyards, soil and water conservation are often implemented. The most widely used measure for soil conservation for vineyards in hilly/mountainous landscapes is terracing. However, while improving vineyards stability, the same changes in hillslope hydrology caused by these anthropogenic structures to favor agricultural activities, often result in situations that may lead to local instabilities. Terraces, in fact, when not properly maintained can create hazards for people and settlements, but also for cultivations and for the related economy. Agricultural roads also serve terraced lands, and the construction of these types of anthropogenic features can have deep effects on water flows, in a way similar to the one already registered for forest roads. The goal of this research is to use Li<span class="hlt">DAR</span> data for the high-resolution hydro-geomorphological analysis of vineyards, underlining the capability of high-resolution topography to provide new tools for a correct management of vineyards terraced landscapes. The work focus on terraced- and road-induced erosion, and it considers a methodology successfully applied to a different environmental context (the RPII index, Tarolli et <span class="hlt">al</span>. 2013). The index is applied to two study areas, located in the center of Italy, where soil erosion and terrace failures represent a critical issue. The results highlight the effectiveness of high-resolution topography in the analysis of surface erosion, thus providing useful tool to schedule a suitable environmental planning for a sustainable development, and so, to mitigate the consequences of the anthropogenic alterations induced by the terraces structures and</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014EGUGA..1611679V','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014EGUGA..1611679V"><span id="translatedtitle">Effects of atmospheric stability on the evolution of wind turbine wakes: Volumetric Li<span class="hlt">DAR</span> scans</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Valerio Iungo, Giacomo; Porté-Agel, Fernando</p> <p>2014-05-01</p> <p>Aerodynamic optimization of wind farm layout is a fundamental task to reduce wake effects on downstream wind turbines, thus to maximize wind power harvesting. However, downstream evolution and recovery of wind turbine wakes are strongly affected by the characteristics of the incoming atmospheric boundary layer (ABL) flow, like the vertical profiles of the mean wind velocity and the turbulence intensity, which are in turn affected by the ABL stability regime. Therefore, the characterization of the variability of wind turbine wakes under different ABL stability regimes becomes fundamental to better predict wind power harvesting and improve wind farm efficiency. To this aim, wind velocity measurements of the wake produced by a 2 MW Enercon E-70 wind turbine were performed with three scanning Doppler wind Light Detection and Ranging (Li<span class="hlt">DAR</span>) instruments. One Li<span class="hlt">DAR</span> was typically devoted to the characterization of the incoming wind, in particular wind velocity, shear and turbulence intensity at the height of the rotor disc. The other two Li<span class="hlt">DARs</span> performed scans in order to characterize the wake velocity field produced by the tested wind turbine. The main challenge in performing field measurements of wind turbine wakes is represented by the varying wind conditions, and by the consequent adjustments of the turbine yaw angle needed to maximize power production. Consequently, taking into account possible variations of the relative position between Li<span class="hlt">DAR</span> measurement volume and wake location, different Li<span class="hlt">DAR</span> measurement procedures were carried out in order to perform 2-D and 3-D characterizations of the mean wake velocity field. However, larger measurement volumes and higher spatial resolution require longer sampling periods; thus, to investigate wake turbulence tests were also performed by staring the Li<span class="hlt">DAR</span> laser beam over fixed directions and with the maximum sampling frequency. Furthermore, volumetric scans of the wind turbine wake were performed under different wind</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3855685','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3855685"><span id="translatedtitle">Using Satellite and Airborne Li<span class="hlt">DAR</span> to Model Woodpecker Habitat Occupancy at the Landscape Scale</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Vierling, Lee A.; Vierling, Kerri T.; Adam, Patrick; Hudak, Andrew T.</p> <p>2013-01-01</p> <p>Incorporating vertical vegetation structure into models of animal distributions can improve understanding of the patterns and processes governing habitat selection. Li<span class="hlt">DAR</span> can provide such structural information, but these data are typically collected via aircraft and thus are limited in spatial extent. Our objective was to explore the utility of satellite-based Li<span class="hlt">DAR</span> data from the Geoscience Laser Altimeter System (GLAS) relative to airborne-based Li<span class="hlt">DAR</span> to model the north Idaho breeding distribution of a forest-dependent ecosystem engineer, the Red-naped sapsucker (Sphyrapicus nuchalis). GLAS data occurred within ca. 64 m diameter ellipses spaced a minimum of 172 m apart, and all occupancy analyses were confined to this grain scale. Using a hierarchical approach, we modeled Red-naped sapsucker occupancy as a function of Li<span class="hlt">DAR</span> metrics derived from both platforms. Occupancy models based on satellite data were weak, possibly because the data within the GLAS ellipse did not fully represent habitat characteristics important for this species. The most important structural variables influencing Red-naped Sapsucker breeding site selection based on airborne Li<span class="hlt">DAR</span> data included foliage height diversity, the distance between major strata in the canopy vertical profile, and the vegetation density near the ground. These characteristics are consistent with the diversity of foraging activities exhibited by this species. To our knowledge, this study represents the first to examine the utility of satellite-based Li<span class="hlt">DAR</span> to model animal distributions. The large area of each GLAS ellipse and the non-contiguous nature of GLAS data may pose significant challenges for wildlife distribution modeling; nevertheless these data can provide useful information on ecosystem vertical structure, particularly in areas of gentle terrain. Additional work is thus warranted to utilize Li<span class="hlt">DAR</span> datasets collected from both airborne and past and future satellite platforms (e.g. GLAS, and the planned IceSAT2</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/24324655','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/24324655"><span id="translatedtitle">Using satellite and airborne Li<span class="hlt">DAR</span> to model woodpecker habitat occupancy at the landscape scale.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Vierling, Lee A; Vierling, Kerri T; Adam, Patrick; Hudak, Andrew T</p> <p>2013-01-01</p> <p>Incorporating vertical vegetation structure into models of animal distributions can improve understanding of the patterns and processes governing habitat selection. Li<span class="hlt">DAR</span> can provide such structural information, but these data are typically collected via aircraft and thus are limited in spatial extent. Our objective was to explore the utility of satellite-based Li<span class="hlt">DAR</span> data from the Geoscience Laser Altimeter System (GLAS) relative to airborne-based Li<span class="hlt">DAR</span> to model the north Idaho breeding distribution of a forest-dependent ecosystem engineer, the Red-naped sapsucker (Sphyrapicus nuchalis). GLAS data occurred within ca. 64 m diameter ellipses spaced a minimum of 172 m apart, and all occupancy analyses were confined to this grain scale. Using a hierarchical approach, we modeled Red-naped sapsucker occupancy as a function of Li<span class="hlt">DAR</span> metrics derived from both platforms. Occupancy models based on satellite data were weak, possibly because the data within the GLAS ellipse did not fully represent habitat characteristics important for this species. The most important structural variables influencing Red-naped Sapsucker breeding site selection based on airborne Li<span class="hlt">DAR</span> data included foliage height diversity, the distance between major strata in the canopy vertical profile, and the vegetation density near the ground. These characteristics are consistent with the diversity of foraging activities exhibited by this species. To our knowledge, this study represents the first to examine the utility of satellite-based Li<span class="hlt">DAR</span> to model animal distributions. The large area of each GLAS ellipse and the non-contiguous nature of GLAS data may pose significant challenges for wildlife distribution modeling; nevertheless these data can provide useful information on ecosystem vertical structure, particularly in areas of gentle terrain. Additional work is thus warranted to utilize Li<span class="hlt">DAR</span> datasets collected from both airborne and past and future satellite platforms (e.g. GLAS, and the planned IceSAT2</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011AGUFMEP51E..05P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011AGUFMEP51E..05P"><span id="translatedtitle">Distinguishing grass from ground using Li<span class="hlt">DAR</span>: Techniques and applications</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Pelletier, J. D.; Swetnam, T.; Papuga, S. A.; Nelson, K.; Brooks, P. D.; Harpold, A. A.; Chorover, J.</p> <p>2011-12-01</p> <p>Standard protocols exist for extracting bare-earth Digital Elevation Models (DEMs) from Li<span class="hlt">DAR</span> point clouds that include trees and other large woody vegetation. Grasses and other herbaceous plants can also obscure the ground surface, yet methods for optimally distinguishing grass from ground to generate accurate Li<span class="hlt">DAR</span>-based raster products for geomorphic and ecological applications are still under development. Developing such methods is important because Li<span class="hlt">DAR</span>-based difference products (e.g. snow thickness) require accurate representations of the ground surface and because raster data for grass height and density have important applications in ecology. In this study, we developed and tested methods for constructing optimal bare-earth and grass height raster layers from Li<span class="hlt">DAR</span> point clouds and compared the results to high-quality field-based measurements of grass height, density, and species type for nearly 1000 precisely geo-referenced locations collected during the acquisition of a >200 km^2 airborne Li<span class="hlt">DAR</span> flight of the Valles Caldera National Preserve (New Mexico). In cases of partially bare ground (where the skewness of return heights above a plane fit to the lowest first returns is sufficiently large), a planar fit to the lowest first returns provides a good method of producing an accurate bare-earth DEM and the statistics of the first returns above that planar fit provide good estimates of the mean and variance of grass height. In areas of relatively thick grass cover, however, a fit to the lowest first returns yields a bare-earth DEM that may be a meter or more above the actual ground surface. Here we propose a method to solve this problem using field-measured correlations among the mean, variance, and skewness of grass heights. In this method, the variance and skewness of the differences between Li<span class="hlt">DAR</span> first returns and a 10m^2 planar fit to the lowest first returns is used, together with field-based correlations of grass height statistics, to estimate the mean</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013AGUFM.H13J1500L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013AGUFM.H13J1500L"><span id="translatedtitle">Application of Li<span class="hlt">DAR</span> to hydrologic flux estimation in Australian eucalypt forests (Invited)</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Lane, P. N.; Mitchell, P. J.; Jaskierniak, D.; Hawthorne, S. N.; Griebel, A.</p> <p>2013-12-01</p> <p>The potential of Li<span class="hlt">DAR</span> in ecohydrology is significant as characterising catchment vegetation is crucial to accurate estimation of evapotranspiration (ET). While this may be done at large scales for model parameterisation, stand-scale applications are equally appropriate where traditional methods of measurement of LAI or sapwood areas are time consuming and reliant on assumptions of representative sampling. This is particularly challenging in mountain forests where aspect, soil properties and energy budgets can vary significantly, reflected in the vegetation or where there are changes in the spatial distribution of structural attributes following disturbance. Recent research has investigated the spatial distribution of ET in a eucalypt forest in SE Australia using plot-scale sapflow, interception and forest floor ET measurements. Li<span class="hlt">DAR</span> was used scale up these measurements. Li<span class="hlt">DAR</span> (0.16 m scanner footprint) canopy indices were correlated via stepwise regression with 4 water use scalars: basal area (BA), sapwood area (SA), leaf area index (LAI) and canopy coverage (C), with Hmed, Hmean, H80, H95 the best predictors. Combining these indices with empirical relationships between SA and BA, and SA and transpiration (T), and inventory plot 'ground truthing' transpiration was estimated across the 1.3 km2 catchment. Interception was scaled via the Gash model with Li<span class="hlt">DAR</span> derived inputs. The up-scaling showed a significant variability in the spatial distribution of ET, related to the distribution of SA. The use of Li<span class="hlt">DAR</span> meant scaling could be achieved at an appropriate spatial scale (20 x 20 m) to the measurements. The second example is the use of airborne Li<span class="hlt">DAR</span> in developing growth forest models for hydrologic modeling. Li<span class="hlt">DAR</span> indices were used to stratify multilayered forests using mixed-effect models with a wide range of theoretical distribution functions. When combined with historical plot-scale inventory data we show demonstrated improved growth modeling over traditional</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010AGUFMEP23A0775Q','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010AGUFMEP23A0775Q"><span id="translatedtitle">An application of vessel-based Li<span class="hlt">DAR</span> to quantify coastal retreat in Southern Monterey Bay, CA during the 2008-2009 year and the 2009-2010 El Nino</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Quan, S.; Kvitek, R. G.; Smith, D. P.</p> <p>2010-12-01</p> <p>Coastal erosion has become a prominent issue in Monterey Bay, California. Areas at high risk include native coastal dunes, private and public beachfront properties, municipal sewage lines, and areas of the highway 1 corridor. Traditional airborne Li<span class="hlt">DAR</span> has been an effective but costly method for measuring coastal topography by providing high resolution and broad coverage. In 1997 and 1998, NASA, USGS, and NOAA collaborated to conduct pre-and post-El Niño airborne Li<span class="hlt">DAR</span> surveys of the California coastline. The anticipation of this ENSO event coupled with Li<span class="hlt">DAR</span> technology resulted in high resolution snapshots of the coastline pre-post El Niño, with analyses yielding erosion rates on the order of nearly seven times the historical annual dune erosion average (Thornton et <span class="hlt">al</span> 2006). Since then, there have been no further, publicly available Li<span class="hlt">DAR</span> surveys of the Monterey Bay shoreline. The goal of this project is to apply a vessel-based Li<span class="hlt">DAR</span> system to measure coastal geomorphology, determine the efficacy of vessel-based topographic Li<span class="hlt">DAR</span> for mapping coastal geomorphology, and quantify the spatial distribution of coastal retreat for Southern Monterey Bay, California during the 2009-10 El Niño and the 2008-2009 normal (non- El Niño) year. The area of study was the Monterey Bay coastline from Monterey harbor, CA north to Marina State Beach at Reservation Road. Sea cliff morphology data were measured on Dec 9th and 10th, 2008, Nov 4th 2009, and on July 15, 16, and 17th 2010 through the use of a terrestrial Li<span class="hlt">DAR</span> system mounted atop the CSUMB Seafloor Mapping Lab’s R/V VenTresca. These vessel based Li<span class="hlt">DAR</span> data were compared using mapping and spatial analysis tools in ArcGIS to quantify the spatial distribution of coastal retreat and calculate erosion rates for the Monterey Bay shoreline during the 2009-2010 El Niño and the 2008-2009 normal year. In keeping with previous published work based on other methods, preliminary results show numerous erosional hotspots which</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/22033763','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/22033763"><span id="translatedtitle">A universal airborne Li<span class="hlt">DAR</span> approach for tropical forest carbon mapping.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Asner, Gregory P; Mascaro, Joseph; Muller-Landau, Helene C; Vieilledent, Ghislain; Vaudry, Romuald; Rasamoelina, Maminiaina; Hall, Jefferson S; van Breugel, Michiel</p> <p>2012-04-01</p> <p>Airborne light detection and ranging (Li<span class="hlt">DAR</span>) is fast turning the corner from demonstration technology to a key tool for assessing carbon stocks in tropical forests. With its ability to penetrate tropical forest canopies and detect three-dimensional forest structure, Li<span class="hlt">DAR</span> may prove to be a major component of international strategies to measure and account for carbon emissions from and uptake by tropical forests. To date, however, basic ecological information such as height-diameter allometry and stand-level wood density have not been mechanistically incorporated into methods for mapping forest carbon at regional and global scales. A better incorporation of these structural patterns in forests may reduce the considerable time needed to calibrate airborne data with ground-based forest inventory plots, which presently necessitate exhaustive measurements of tree diameters and heights, as well as tree identifications for wood density estimation. Here, we develop a new approach that can facilitate rapid Li<span class="hlt">DAR</span> calibration with minimal field data. Throughout four tropical regions (Panama, Peru, Madagascar, and Hawaii), we were able to predict aboveground carbon density estimated in field inventory plots using a single universal Li<span class="hlt">DAR</span> model (r ( 2 ) = 0.80, RMSE = 27.6 Mg C ha(-1)). This model is comparable in predictive power to locally calibrated models, but relies on limited inputs of basal area and wood density information for a given region, rather than on traditional plot inventories. With this approach, we propose to radically decrease the time required to calibrate airborne Li<span class="hlt">DAR</span> data and thus increase the output of high-resolution carbon maps, supporting tropical forest conservation and climate mitigation policy. PMID:22033763</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li class="active"><span>15</span></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_15 --> <div id="page_16" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li class="active"><span>16</span></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="301"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012Geomo.173...30V','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012Geomo.173...30V"><span id="translatedtitle">Object-oriented identification of forested landslides with derivatives of single pulse Li<span class="hlt">DAR</span> data</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Van Den Eeckhaut, Miet; Kerle, Norman; Poesen, Jean; Hervás, Javier</p> <p>2012-11-01</p> <p>In contrast to the many studies that use expert-based analysis of Li<span class="hlt">DAR</span> derivatives for landslide mapping in forested terrain, only few studies have attempted to develop (semi-)automatic methods for extracting landslides from Li<span class="hlt">DAR</span> derivatives. While all these studies are pixel-based, it has not yet been tested whether object-oriented analysis (OOA) could be an alternative. This study investigates the potential of OOA using only single-pulse Li<span class="hlt">DAR</span> derivatives, such as slope gradient, roughness and curvature to map landslides. More specifically, the focus is on both Li<span class="hlt">DAR</span> data segmentation and classification of slow-moving landslides in densely vegetated areas, where spectral data do not allow accurate landslide identification. A multistage procedure has been developed and tested in the Flemish Ardennes (Belgium). The procedure consists of (1) image binarization and multiresolution segmentation, (2) classification of landslide parts (main scarps and landslide body segments) and non-landslide features (i.e. earth banks and cropland fields) with supervised support vector machines at the appropriate scale, (3) delineation of landslide flanks, (4) growing of a landslide body starting from its main scarp, and (5) final cleaning of the inventory map. The results obtained show that OOA using Li<span class="hlt">DAR</span> derivatives allows recognition and characterization of profound morphologic properties of forested deep-seated landslides on soil-covered hillslopes, because more than 90% of the main scarps and 70% of the landslide bodies of an expert-based inventory were accurately identified with OOA. For mountainous areas with bedrock, on the other hand, creation of a transferable model is expected to be more difficult.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2014ISPAr.XL3....1A&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2014ISPAr.XL3....1A&link_type=ABSTRACT"><span id="translatedtitle">Li<span class="hlt">DAR</span> Segmentation using Suitable Seed Points for 3D Building Extraction</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Abdullah, S. M.; Awrangjeb, M.; Lu, G.</p> <p>2014-08-01</p> <p>Effective building detection and roof reconstruction has an influential demand over the remote sensing research community. In this paper, we present a new automatic Li<span class="hlt">DAR</span> point cloud segmentation method using suitable seed points for building detection and roof plane extraction. Firstly, the Li<span class="hlt">DAR</span> point cloud is separated into "ground" and "non-ground" points based on the analysis of DEM with a height threshold. Each of the non-ground point is marked as coplanar or non-coplanar based on a coplanarity analysis. Commencing from the maximum Li<span class="hlt">DAR</span> point height towards the minimum, all the Li<span class="hlt">DAR</span> points on each height level are extracted and separated into several groups based on 2D distance. From each group, lines are extracted and a coplanar point which is the nearest to the midpoint of each line is considered as a seed point. This seed point and its neighbouring points are utilised to generate the plane equation. The plane is grown in a region growing fashion until no new points can be added. A robust rule-based tree removal method is applied subsequently to remove planar segments on trees. Four different rules are applied in this method. Finally, the boundary of each object is extracted from the segmented Li<span class="hlt">DAR</span> point cloud. The method is evaluated with six different data sets consisting hilly and densely vegetated areas. The experimental results indicate that the proposed method offers a high building detection and roof plane extraction rates while compared to a recently proposed method.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2015ISPArXL15..595R&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2015ISPArXL15..595R&link_type=ABSTRACT"><span id="translatedtitle">Building Damage Assessment after Earthquake Using Post-Event Li<span class="hlt">DAR</span> Data</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Rastiveis, H.; Eslamizade, F.; Hosseini-Zirdoo, E.</p> <p>2015-12-01</p> <p>After an earthquake, damage assessment plays an important role in leading rescue team to help people and decrease the number of mortality. Damage map is a map that demonstrates collapsed buildings with their degree of damage. With this map, finding destructive buildings can be quickly possible. In this paper, we propose an algorithm for automatic damage map generation after an earthquake using post-event Li<span class="hlt">DAR</span> Data and pre-event vector map. The framework of the proposed approach has four main steps. To find the location of all buildings on Li<span class="hlt">DAR</span> data, in the first step, Li<span class="hlt">DAR</span> data and vector map are registered by using a few number of ground control points. Then, building layer, selected from vector map, are mapped on the Li<span class="hlt">DAR</span> data and all pixels which belong to the buildings are extracted. After that, through a powerful classifier all the extracted pixels are classified into three classes of "debris", "intact building" and "unclassified". Since textural information make better difference between "debris" and "intact building" classes, different textural features are applied during the classification. After that, damage degree for each candidate building is estimated based on the relation between the numbers of pixels labelled as "debris" class to the whole building area. Calculating the damage degree for each candidate building, finally, building damage map is generated. To evaluate the ability proposed method in generating damage map, a data set from Port-au-Prince, Haiti's capital after the 2010 Haiti earthquake was used. In this case, after calculating of all buildings in the test area using the proposed method, the results were compared to the damage degree which estimated through visual interpretation of post-event satellite image. Obtained results were proved the reliability of the proposed method in damage map generation using Li<span class="hlt">DAR</span> data.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015AGUFM.H41E1379P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015AGUFM.H41E1379P"><span id="translatedtitle">Water turbidity estimation from airborne hyperspectral imagery and full waveform bathymetric Li<span class="hlt">DAR</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Pan, Z.; Glennie, C. L.; Fernandez-Diaz, J. C.</p> <p>2015-12-01</p> <p>The spatial and temporal variations in water turbidity are of great interest for the study of fluvial and coastal environments; and for predicting the performance of remote sensing systems that are used to map these. Conventional water turbidity estimates from remote sensing observations have normally been derived using near infrared reflectance. We have investigated the potential of determining water turbidity from additional remote sensing sources, namely airborne hyperspectral imagery and single wavelength bathymetric Li<span class="hlt">DAR</span> (Light Detection and Ranging). The confluence area of the Blue and Colorado River, CO was utilized as a study area to investigate the capabilities of both airborne bathymetric Li<span class="hlt">DAR</span> and hyperspectral imagery for water turbidity estimation. Discrete and full waveform bathymetric data were collected using Optech's Gemini (1064 nm) and Aquarius (532 nm) Li<span class="hlt">DAR</span> sensors. Hyperspectral imagery (1.2 m pixel resolution and 72 spectral bands) was acquired using an ITRES CASI-1500 imaging system. As an independent reference, measurements of turbidity were collected concurrent with the airborne remote sensing acquisitions, using a WET Labs EcoTriplet deployed from a kayak and turbidity was then derived from the measured backscatter. The bathymetric full waveform dataset contains a discretized sample of the full backscatter of water column and benthic layer. Therefore, the full waveform records encapsulate the water column characteristics of turbidity. A nonparametric support vector regression method is utilized to estimate water turbidity from both hyperspectral imagery and voxelized full waveform Li<span class="hlt">DAR</span> returns, both individually and as a fused dataset. Results of all the evaluations will be presented, showing an initial turbidity prediction accuracy of approximately 1.0 NTU. We will also discuss our future strategy for enhanced fusion of the full waveform Li<span class="hlt">DAR</span> and hyperspectral imagery for improved turbidity estimation.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015ISPAr.XL3..189S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015ISPAr.XL3..189S"><span id="translatedtitle">Mapping the Risk of Forest Wind Damage Using Airborne Scanning Li<span class="hlt">DAR</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Saarinen, N.; Vastaranta, M.; Honkavaara, E.; Wulder, M. A.; White, J. C.; Litkey, P.; Holopainen, M.; Hyyppä, J.</p> <p>2015-03-01</p> <p>Wind damage is known for causing threats to sustainable forest management and yield value in boreal forests. Information about wind damage risk can aid forest managers in understanding and possibly mitigating damage impacts. The objective of this research was to better understand and quantify drivers of wind damage, and to map the probability of wind damage. To accomplish this, we used open-access airborne scanning light detection and ranging (Li<span class="hlt">DAR</span>) data. The probability of wind-induced forest damage (PDAM) in southern Finland (61°N, 23°E) was modelled for a 173 km2 study area of mainly managed boreal forests (dominated by Norway spruce and Scots pine) and agricultural fields. Wind damage occurred in the study area in December 2011. Li<span class="hlt">DAR</span> data were acquired prior to the damage in 2008. High spatial resolution aerial imagery, acquired after the damage event (January, 2012) provided a source of model calibration via expert interpretation. A systematic grid (16 m x 16 m) was established and 430 sample grid cells were identified systematically and classified as damaged or undamaged based on visual interpretation using the aerial images. Potential drivers associated with PDAM were examined using a multivariate logistic regression model. Risk model predictors were extracted from the Li<span class="hlt">DAR</span>-derived surface models. Geographic information systems (GIS) supported spatial mapping and identification of areas of high PDAM across the study area. The risk model based on Li<span class="hlt">DAR</span> data provided good agreement with detected risk areas (73 % with kappa-value 0,47). The strongest predictors in the risk model were mean canopy height and mean elevation. Our results indicate that open-access Li<span class="hlt">DAR</span> data sets can be used to map the probability of wind damage risk without field data, providing valuable information for forest management planning.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2015IJAEO..37...56R&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2015IJAEO..37...56R&link_type=ABSTRACT"><span id="translatedtitle">Combined use of Li<span class="hlt">DAR</span> data and multispectral earth observation imagery for wetland habitat mapping</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Rapinel, Sébastien; Hubert-Moy, Laurence; Clément, Bernard</p> <p>2015-05-01</p> <p>Although wetlands play a key role in controlling flooding and nonpoint source pollution, sequestering carbon and providing an abundance of ecological services, the inventory and characterization of wetland habitats are most often limited to small areas. This explains why the understanding of their ecological functioning is still insufficient for a reliable functional assessment on areas larger than a few hectares. While Li<span class="hlt">DAR</span> data and multispectral Earth Observation (EO) images are often used separately to map wetland habitats, their combined use is currently being assessed for different habitat types. The aim of this study is to evaluate the combination of multispectral and multiseasonal imagery and Li<span class="hlt">DAR</span> data to precisely map the distribution of wetland habitats. The image classification was performed combining an object-based approach and decision-tree modeling. Four multispectral images with high (SPOT-5) and very high spatial resolution (Quickbird, KOMPSAT-2, aerial photographs) were classified separately. Another classification was then applied integrating summer and winter multispectral image data and three layers derived from Li<span class="hlt">DAR</span> data: vegetation height, microtopography and intensity return. The comparison of classification results shows that some habitats are better identified on the winter image and others on the summer image (overall accuracies = 58.5 and 57.6%). They also point out that classification accuracy is highly improved (overall accuracy = 86.5%) when combining Li<span class="hlt">DAR</span> data and multispectral images. Moreover, this study highlights the advantage of integrating vegetation height, microtopography and intensity parameters in the classification process. This article demonstrates that information provided by the synergetic use of multispectral images and Li<span class="hlt">DAR</span> data can help in wetland functional assessment</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016JHyd..533..343Z','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016JHyd..533..343Z"><span id="translatedtitle">Applying a weighted random forests method to extract karst sinkholes from Li<span class="hlt">DAR</span> data</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Zhu, Junfeng; Pierskalla, William P.</p> <p>2016-02-01</p> <p>Detailed mapping of sinkholes provides critical information for mitigating sinkhole hazards and understanding groundwater and surface water interactions in karst terrains. Li<span class="hlt">DAR</span> (Light Detection and Ranging) measures the earth's surface in high-resolution and high-density and has shown great potentials to drastically improve locating and delineating sinkholes. However, processing Li<span class="hlt">DAR</span> data to extract sinkholes requires separating sinkholes from other depressions, which can be laborious because of the sheer number of the depressions commonly generated from Li<span class="hlt">DAR</span> data. In this study, we applied the random forests, a machine learning method, to automatically separate sinkholes from other depressions in a karst region in central Kentucky. The sinkhole-extraction random forest was grown on a training dataset built from an area where Li<span class="hlt">DAR</span>-derived depressions were manually classified through a visual inspection and field verification process. Based on the geometry of depressions, as well as natural and human factors related to sinkholes, 11 parameters were selected as predictive variables to form the dataset. Because the training dataset was imbalanced with the majority of depressions being non-sinkholes, a weighted random forests method was used to improve the accuracy of predicting sinkholes. The weighted random forest achieved an average accuracy of 89.95% for the training dataset, demonstrating that the random forest can be an effective sinkhole classifier. Testing of the random forest in another area, however, resulted in moderate success with an average accuracy rate of 73.96%. This study suggests that an automatic sinkhole extraction procedure like the random forest classifier can significantly reduce time and labor costs and makes its more tractable to map sinkholes using Li<span class="hlt">DAR</span> data for large areas. However, the random forests method cannot totally replace manual procedures, such as visual inspection and field verification.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2011AGUFM.C33D0672T&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2011AGUFM.C33D0672T&link_type=ABSTRACT"><span id="translatedtitle">Spatial accounting for errors in Li<span class="hlt">DAR</span>-derived products: Snow volume and snow water equivalent estimation</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Tinkham, W. T.; Hoffman, C. M.; Falkowski, M. J.; Smith, A. M.; Link, T. E.; Marshall, H.</p> <p>2011-12-01</p> <p>Light Detection and Ranging (Li<span class="hlt">DAR</span>) has become one of the most effective and reliable means of characterizing surface topography and vegetation structure. Most Li<span class="hlt">DAR</span>-derived estimates such as vegetation height, snow depth, and floodplain boundaries rely on the accurate creation of digital terrain models (DTM). As a result of the importance of an accurate DTM in using Li<span class="hlt">DAR</span> data to estimate snow depth, it is necessary to understand the variables that influence the DTM accuracy in order to assess snow depth error. A series of 4 x 4 m plots that were surveyed at 0.5 m spacing in a semi-arid catchment were used for training the Random Forests algorithm along with a series of 35 variables in order to spatially predict vertical error within a Li<span class="hlt">DAR</span> derived DTM. The final model was utilized to predict the combined error resulting from snow volume and snow water equivalent estimates derived from a snow-free Li<span class="hlt">DAR</span> DTM and a snow-on Li<span class="hlt">DAR</span> acquisition of the same site. The methodology allows for a statistical quantification of the spatially-distributed error patterns that are incorporated into the estimation of snow volume and snow water equivalents from Li<span class="hlt">DAR</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/26250147','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/26250147"><span id="translatedtitle">Development and validation of the Dimensional Anhedonia Rating Scale (<span class="hlt">DARS</span>) in a community sample and individuals with major depression.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Rizvi, Sakina J; Quilty, Lena C; Sproule, Beth A; Cyriac, Anna; Michael Bagby, R; Kennedy, Sidney H</p> <p>2015-09-30</p> <p>Anhedonia, a core symptom of Major Depressive Disorder (MDD), is predictive of antidepressant non-response. In contrast to the definition of anhedonia as a "loss of pleasure", neuropsychological studies provide evidence for multiple facets of hedonic function. The aim of the current study was to develop and validate the Dimensional Anhedonia Rating Scale (<span class="hlt">DARS</span>), a dynamic scale that measures desire, motivation, effort and consummatory pleasure across hedonic domains. Following item selection procedures and reliability testing using data from community participants (N=229) (Study 1), the 17-item scale was validated in an online study with community participants (N=150) (Study 2). The <span class="hlt">DARS</span> was also validated in unipolar or bipolar depressed patients (n=52) and controls (n=50) (Study 3). Principal components analysis of the 17-item <span class="hlt">DARS</span> revealed a 4-component structure mapping onto the domains of anhedonia: hobbies, food/drink, social activities, and sensory experience. Reliability of the <span class="hlt">DARS</span> subscales was high across studies (Cronbach's α=0.75-0.92). The <span class="hlt">DARS</span> also demonstrated good convergent and divergent validity. Hierarchical regression analysis revealed the <span class="hlt">DARS</span> showed additional utility over the Snaith-Hamilton Pleasure Scale (SHAPS) in predicting reward function and distinguishing MDD subgroups. These studies provide support for the reliability and validity of the <span class="hlt">DARS</span>. PMID:26250147</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012EGUGA..14.8708I','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012EGUGA..14.8708I"><span id="translatedtitle">Multi-component wind measurements of wind turbine wakes performed with three Li<span class="hlt">DARs</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Iungo, G. V.; Wu, Y.-T.; Porté-Agel, F.</p> <p>2012-04-01</p> <p>Field measurements of the wake flow produced from the interaction between atmospheric boundary layer and a wind turbine are performed with three wind Li<span class="hlt">DARs</span>. The tested wind turbine is a 2 MW Enercon E-70 located in Collonges, Switzerland. First, accuracy of mean values and frequency resolution of the wind measurements are surveyed as a function of the number of laser rays emitted for each measurement. Indeed, measurements performed with one single ray allow maximizing sampling frequency, thus characterizing wake turbulence. On the other hand, if the number of emitted rays is increased accuracy of mean wind is increased due to the longer sampling period. Subsequently, two-dimensional measurements with a single Li<span class="hlt">DAR</span> are carried out over vertical sections of the wind turbine wake and mean wake flow is obtained by averaging 2D measurements consecutively performed. The high spatial resolution of the used Li<span class="hlt">DAR</span> allows characterizing in details velocity defect present in the central part of the wake and its downstream recovery. Single Li<span class="hlt">DAR</span> measurements are also performed by staring the laser beam at fixed directions for a sampling period of about ten minutes and maximizing the sampling frequency in order to characterize wake turbulence. From these tests wind fluctuation peaks are detected in the wind turbine wake at blade top-tip height for different downstream locations. The magnitude of these turbulence peaks is generally reduced by moving downstream. This increased turbulence level at blade top-tip height observed for a real wind turbine has been already detected from previous wind tunnel tests and Large Eddy simulations, thus confirming the presence of a source of dangerous fatigue loads for following wind turbines within a wind farm. Furthermore, the proper characterization of wind fluctuations through Li<span class="hlt">DAR</span> measurements is proved by the detection of the inertial subrange from spectral analysis of these velocity signals. Finally, simultaneous measurements with two</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2010EGUGA..12.8169V&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2010EGUGA..12.8169V&link_type=ABSTRACT"><span id="translatedtitle">Change detection of riverbed movements using river cross-sections and Li<span class="hlt">DAR</span> data</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Vetter, Michael; Höfle, Bernhard; Mandlburger, Gottfried; Rutzinger, Martin</p> <p>2010-05-01</p> <p>Today, Airborne Li<span class="hlt">DAR</span> derived digital terrain models (DTMs) are used for several aspects in different scientific disciplines, such as hydrology, geomorphology or archaeology. In the field of river geomorphology, Li<span class="hlt">DAR</span> data sets can provide information on the riverine vegetation, the level and boundary of the water body, the elevation of the riparian foreland and their roughness. The Li<span class="hlt">DAR</span> systems in use for topographic data acquisition mainly operate with wavelengths of at least 1064nm and, thus, are not able to penetrate water. Li<span class="hlt">DAR</span> sensors with two wavelengths are available (bathymetric Li<span class="hlt">DAR</span>), but they can only provide elevation information of riverbeds or lakes, if the water is clear and the minimum water depth exceeds 1.5m. In small and shallow rivers it is impossible to collect information of the riverbed, regardless of the used Li<span class="hlt">DAR</span> sensor. In this article, we present a method to derive a high-resolution DTM of the riverbed and to combine it with the Li<span class="hlt">DAR</span> DTM resulting in a watercourse DTM (DTM-W) as a basis for calculating the changes in the riverbed during several years. To obtain such a DTM-W we use river cross-sections acquired by terrestrial survey or echo-sounding. First, a differentiation between water and land has to be done. A highly accurate water surface can be derived by using a water surface delineation algorithm, which incorporates the amplitude information of the Li<span class="hlt">DAR</span> point cloud and additional geometrical features (e.g. local surface roughness). The second step is to calculate a thalweg line, which is the lowest flow path in the riverbed. This is achieved by extracting the lowest point of each river cross section and by fitting a B-spline curve through those points. In the next step, the centerline of the river is calculated by applying a shrinking algorithm of the water boundary polygon. By averaging the thalweg line and the centerline, a main flow path line can be computed. Subsequently, a dense array of 2D-profiles perpendicular to the</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010ECSS...89..200C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010ECSS...89..200C"><span id="translatedtitle">Capabilities of the bathymetric Hawk Eye Li<span class="hlt">DAR</span> for coastal habitat mapping: A case study within a Basque estuary</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Chust, Guillem; Grande, Maitane; Galparsoro, Ibon; Uriarte, Adolfo; Borja, Ángel</p> <p>2010-10-01</p> <p>The bathymetric Li<span class="hlt">DAR</span> system is an airborne laser that detects sea bottom at high vertical and horizontal resolutions in shallow coastal waters. This study assesses the capabilities of the airborne bathymetric Li<span class="hlt">DAR</span> sensor (Hawk Eye system) for coastal habitat mapping in the Oka estuary (within the Biosphere Reserve of Urdaibai, SE Bay of Biscay, northern Spain), where water conditions are moderately turbid. Three specific objectives were addressed: 1) to assess the data quality of the Hawk Eye Li<span class="hlt">DAR</span>, both for terrestrial and subtidal zones, in terms of height measurement density, coverage, and vertical accuracy; 2) to compare bathymetric Li<span class="hlt">DAR</span> with a ship-borne multibeam echosounder (MBES) for different bottom types and depth ranges; and 3) to test the discrimination potential of Li<span class="hlt">DAR</span> height and reflectance information, together with multi-spectral imagery (three visible and near infrared bands), for the classification of 22 salt marsh and rocky shore habitats, covering supralittoral, intertidal and subtidal zones. The bathymetric Li<span class="hlt">DAR</span> Hawk Eye data enabled the generation of a digital elevation model (DEM) of the Oka estuary, at 2 m of horizontal spatial resolution in the terrestrial zone (with a vertical accuracy of 0.15 m) and at 4 m within the subtidal, extending a water depth of 21 m. Data gaps occurred in 14.4% of the area surveyed with the Li<span class="hlt">DAR</span> (13.69 km 2). Comparison of the Li<span class="hlt">DAR</span> system and the MBES showed no significant mean difference in depth. However, the Root Mean Square error of the former was high (0.84 m), especially concentrated upon rocky (0.55-1.77 m) rather than in sediment bottoms (0.38-0.62 m). The potential of Li<span class="hlt">DAR</span> topographic variables and reflectance alone for discriminating 15 intertidal and submerged habitats was low (with overall classification accuracy between 52.4 and 65.4%). In particular, reflectance retrieved for this case study has been found to be not particularly useful for classification purposes. The combination of the Li<span class="hlt">DAR</span></p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2013AGUFM.H23E1318M&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2013AGUFM.H23E1318M&link_type=ABSTRACT"><span id="translatedtitle">Importance of High-Resolution Li<span class="hlt">DAR</span> Data in Modeling Runoff Levels Over Impervious Surfaces</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Melosh, C.; Rao, M.</p> <p>2013-12-01</p> <p>Directly connected impervious areas collect and deliver unfiltered runoff to modified and impacted waterways. Modeling water flow over the landscape is an effective method of observing drainage patterns and predicting pollutant and sediment loadings. Improved models applying high-resolution elevation data can identify key areas with high pollutant output. This is a crucial issue in the Lake Tahoe Basin where lakeshore urban development has increased and lake clarity has been declining for years. This study aims to evaluate an integrated Li<span class="hlt">DAR</span> and GIS-based modeling approach that uses a fine-scaled ground surface and impervious surface connectivity to predict the pollutant load in the Lake Tahoe Basin This study produced a fine-scaled surface model of nine subset catchments in the South Tahoe basin, including areas of low (below 20%), medium (30% to 50%) and high (above 50%) impervious surface cover. Our method integrated Li<span class="hlt">DAR</span>, multispectral imagery, and GIS data to develop accurate terrain models, hydrologic routing, and directly connected impervious area layers for the Lake Tahoe basin. The high-density ground and object elevation data collected using Light Detection and Ranging (Li<span class="hlt">DAR</span>) creates an accurate picture of water flow over the land, and obstacles to the flow such as buildings. High-resolution Li<span class="hlt">DAR</span> data was obtained from the Round 10 Lake Tahoe Southern Nevada Public Land Management capital program from the year 2010. This data was processed to create a digital elevation model of the ground surface. Land use classification used object height information from the Li<span class="hlt">DAR</span> cloud, NAIP 4-band images with 1-meter resolution and a normalized difference vegetation index image derived from the NAIP imagery. The US Army Core of Engineers hydrologic modeling system (HEC-HMS) will be used to model runoff. Based on long-term simulations the effect of directly connected impervious area on rainfall-runoff characteristics for the South Lake Tahoe catchments will be</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013AGUFM.H13J1497T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013AGUFM.H13J1497T"><span id="translatedtitle">Quantifying spatial distribution of snow depth errors from Li<span class="hlt">DAR</span> using Random Forests</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Tinkham, W.; Smith, A. M.; Marshall, H.; Link, T. E.; Falkowski, M. J.; Winstral, A. H.</p> <p>2013-12-01</p> <p>There is increasing need to characterize the distribution of snow in complex terrain using remote sensing approaches, especially in isolated mountainous regions that are often water-limited, the principal source of terrestrial freshwater, and sensitive to climatic shifts and variations. We apply intensive topographic surveys, multi-temporal Li<span class="hlt">DAR</span>, and Random Forest modeling to quantify snow volume and characterize associated errors across seven land cover types in a semi-arid mountainous catchment at a 1 and 4 m spatial resolution. The Li<span class="hlt">DAR</span>-based estimates of both snow-off surface topology and snow depths were validated against ground-based measurements across the catchment. Comparison of Li<span class="hlt">DAR</span>-derived snow depths to manual snow depth surveys revealed that Li<span class="hlt">DAR</span> based estimates were more accurate in areas of low lying vegetation such as shrubs (RMSE = 0.14 m) as compared to areas consisting of tree cover (RMSE = 0.20-0.35 m). The highest errors were found along the edge of conifer forests (RMSE = 0.35 m), however a second conifer transect outside the catchment had much lower errors (RMSE = 0.21 m). This difference is attributed to the wind exposure of the first site that led to highly variable snow depths at short spatial distances. The Random Forest modeled errors deviated from the field measured errors with a RMSE of 0.09-0.34 m across the different cover types. Results show that snow drifts, which are important for maintaining spring and summer stream flows and establishing and sustaining water-limited plant species, contained 30 × 5-6% of the snow volume while only occupying 10% of the catchment area similar to findings by prior physically-based modeling approaches. This study demonstrates the potential utility of combining multi-temporal Li<span class="hlt">DAR</span> with Random Forest modeling to quantify the distribution of snow depth with a reasonable degree of accuracy. Future work could explore the utility of Terrestrial Li<span class="hlt">DAR</span> Scanners to produce validation of snow-on surface</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://pubs.er.usgs.gov/publication/70034405','USGSPUBS'); return false;" href="http://pubs.er.usgs.gov/publication/70034405"><span id="translatedtitle">Investigating the spatial distribution of water levels in the Mackenzie Delta using airborne Li<span class="hlt">DAR</span></span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Hopkinson, C.; Crasto, N.; Marsh, P.; Forbes, D.; Lesack, L.</p> <p>2011-01-01</p> <p>Airborne light detection and ranging (Li<span class="hlt">DAR</span>) data were used to map water level (WL) and hydraulic gradients (??H/??x) in the Mackenzie Delta. The Li<span class="hlt">DAR</span> WL data were validated against eight independent hydrometric gauge measurements and demonstrated mean offsets from - 0??22 to + 0??04 m (??< 0??11). Li<span class="hlt">DAR</span>-based WL gradients could be estimated with confidence over channel lengths exceeding 5-10 km where the WL change exceeded local noise levels in the Li<span class="hlt">DAR</span> data. For the entire Delta, the Li<span class="hlt">DAR</span> sample coverage indicated a rate of change in longitudinal gradient (??2H/??x) of 5??5 ?? 10-10 m m-2; therefore offering a potential means to estimate average flood stage hydraulic gradient for areas of the Delta not sampled or monitored. In the Outer Delta, within-channel and terrain gradient measurements all returned a consistent estimate of - 1 ?? 10-5 m m-1, suggesting that this is a typical hydraulic gradient for the downstream end of the Delta. For short reaches (<10 km) of the Peel and Middle Channels in the middle of the Delta, significant and consistent hydraulic gradient estimates of - 5 ?? 10-5 m m-1 were observed. Evidence that hydraulic gradients can vary over short distances, however, was observed in the Peel Channel immediately upstream of Aklavik. A positive elevation anomaly (bulge) of > 0??1 m was observed at a channel constriction entering a meander bend, suggesting a localized modification of the channel hydraulics. Furthermore, water levels in the anabranch channels of the Peel River were almost 1 m higher than in Middle Channel of the Mackenzie River. This suggests: (i) the channels are elevated and have shallower bank heights in this part of the delta, leading to increased cross-delta and along-channel hydraulic gradients; and/or (ii) a proportion of the Peel River flow is lost to Middle Channel due to drainage across the delta through anastamosing channels. This study has demonstrated that airborne Li<span class="hlt">DAR</span> data contain valuable information describing</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2009EGUGA..11.4630H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2009EGUGA..11.4630H"><span id="translatedtitle">Potential of Airborne Li<span class="hlt">DAR</span> in Geomorphology - A Technological Perspective</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Höfle, B.; Mandlburger, G.; Pfeifer, N.; Rutzinger, M.; Bell, R.</p> <p>2009-04-01</p> <p>Airborne Li<span class="hlt">DAR</span>, also referred to as Airborne Laser Scanning, is widely used for high-resolution topographic data acquisition, offering a planimetric (<50cm) and vertical accuracy (<20cm) suited for many applications (e.g. in natural hazard management, forestry). Due to the direct determination of elevation and the penetration capabilities of the laser beam through gaps in vegetation, the Li<span class="hlt">DAR</span> technology exceeds other methods such as stereo-photogrammetry or interferometric SAR particularly in vegetated areas. This contribution gives a review of recent developments of Li<span class="hlt">DAR</span> systems but also advances in data processing, resulting in a higher data density and quality for geomorphological applications. Besides the elevation information most systems additionally record the strength of the received backscatter or even the full temporal distribution of the received energy (i.e. full-waveform). This radiometric information is a valuable parameter for further classification of the scanned areas, in particular for objects being not distinguishable by their geometry. In geomorphology airborne Li<span class="hlt">DAR</span> data can either be used directly in the form of digital elevation data (e.g. digital terrain and surface model, original point cloud) and therein detected surface discontinuities (e.g. breaklines, lineaments) and forms (e.g. fans, rock glaciers), or indirectly by classification of surface features (e.g. vegetation and water) relevant for geomorphological processes. Furthermore, these datasets can be used for visual interpretation and mapping by experts or for automatic derivation of land-surface parameters by means of geomorphometry. With the availability of multitemporal datasets the investigation and quantification of dynamic processes becomes possible. Recent studies show the advantages by using full-waveform Li<span class="hlt">DAR</span> system, which enable an improved echo detection and radiometric calibration of the received backscatter. The availability of additional echo attributes (e</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014JARS....8.3529S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014JARS....8.3529S"><span id="translatedtitle">Evaluation of the contribution of Li<span class="hlt">DAR</span> data and postclassification procedures to object-based classification accuracy</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Styers, Diane M.; Moskal, L. Monika; Richardson, Jeffrey J.; Halabisky, Meghan A.</p> <p>2014-01-01</p> <p>Object-based image analysis (OBIA) is becoming an increasingly common method for producing land use/land cover (LULC) classifications in urban areas. In order to produce the most accurate LULC map, Li<span class="hlt">DAR</span> data and postclassification procedures are often employed, but their relative contributions to accuracy are unclear. We examined the contribution of Li<span class="hlt">DAR</span> data and postclassification procedures to increase classification accuracies over using imagery alone and assessed sources of error along an ecologically complex urban-to-rural gradient in Olympia, Washington. Overall classification accuracy and user's and producer's accuracies for individual classes were evaluated. The addition of Li<span class="hlt">DAR</span> data to the OBIA classification resulted in an 8.34% increase in overall accuracy, while manual postclassification to the imagery+Li<span class="hlt">DAR</span> classification improved accuracy only an additional 1%. Sources of error in this classification were largely due to edge effects, from which multiple different types of errors result.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013AGUFMNH21B1516K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013AGUFMNH21B1516K"><span id="translatedtitle">Landslide investigation using Li<span class="hlt">DAR</span> data acquired by an unmanned helicopter</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kasai, M.; Tanaka, Y.; Marutani, T.; Saito, Y.</p> <p>2013-12-01</p> <p>In this study, Li<span class="hlt">DAR</span> data acquired over 0.5 km2 landslide prone area by an unmanned helicopter is presented. The data was taken in summer 2012 and 2013, when tree foliage covered the ground surface. Imagery was of sufficient quality to identify and measure landslide features. These data together with Li<span class="hlt">DAR</span> data obtained by a manned helicopter in the same area in August 2008 were examined to find active slopes on landslides during the period from 2008 to 2013. Morphological characteristics of these slopes were also analyzed to utilize the notion to discover active but hiding landslides in the region. In inapproachable areas, the UAV (Unmanned Aerial Vehicles) is likely to be of greatest use. In addition, this study showed that repeat monitoring of sites is a way of utilizing UAVs, particularly in terms of cost and convenience.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013SPIE.8737E..0ET','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013SPIE.8737E..0ET"><span id="translatedtitle">Characterization of the OPAL obscurant penetrating Li<span class="hlt">DAR</span> in various degraded visual environments</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Trickey, Evan; Church, Philip; Cao, Xiaoying</p> <p>2013-05-01</p> <p>The OPAL obscurant penetrating Li<span class="hlt">DAR</span> was developed by Neptec and characterized in various degraded visual environments (DVE) over the past five years. Quantitative evaluations of obscurant penetration were performed using the Defence RD Canada - Valcartier (DRDC Valcartier) instrumented aerosol chamber for obscurants such as dust and fog. Experiments were done with the sensor both at a standoff distance and totally engulfed in the obscurants. Field trials were also done to characterize the sensor in snow conditions and in smoke. Finally, the OPAL was also mounted on a Bell 412 helicopter to characterize its dust penetration capabilities, in environment such as Yuma Proving Ground. The paper provides a summary of the results of the OPAL evaluations demonstrating it to be a true "see through" obscurant penetrating Li<span class="hlt">DAR</span> and explores commercial applications of the technology.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012AGUFMEP31C0832R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012AGUFMEP31C0832R"><span id="translatedtitle">Quantifying post-wildfire erosion patterns using terrestrial Li<span class="hlt">DAR</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Rengers, F.; Tucker, G. E.; Moody, J. A.</p> <p>2012-12-01</p> <p>Wildfires are becoming increasingly frequent in the western United States. In burned landscapes, geomorphic change can take place rapidly during rainstorms following a wildfire. Rainfall over a burned area tends to mobilize more sediment than in unburned basins because the wildfire changes soil properties, creating more overland flow. A dearth of ground debris allows for deeper and faster flow that can entrain sediment. We apply terrestrial Li<span class="hlt">DAR</span> to post-wildfire geomorphic change analysis to determine the pattern and magnitude of erosion following rain storms. By differencing digital elevation models created from terrestrial Li<span class="hlt">DAR</span> surveys, we can measure post-wildfire geomorphic change. Topographic analysis with Li<span class="hlt">DAR</span> allows us to monitor landscape recovery and evolution following a wildfire. Traditional methods of post-wildfire erosion analysis have focused on measurements such as erosion pins and silt fences. These capture erosion or deposition at a point or cumulative deposition of the sediment from some unknown contributing area upstream of the silt fence. This requires researchers to integrate measurements over a large area to determine basin-wide erosion. By contrast, successive terrestrial Li<span class="hlt">DAR</span> surveys allow us to map changes in topography over an entire basin or hillslope to determine the spatial distribution of erosion within a basin or on a hillslope and to correlate the erosion with the hydrologic processes between surveys. Our study site is a high-severity burn hillslope, burned by the 2010 Fourmile Canyon fire about 15 km west of Boulder, CO. The wildfire was contained on 16 September 2010 and the first Li<span class="hlt">DAR</span> survey was on 7 October 2010 prior to any significant rain storms. Following this baseline survey, we have used terrestrial Li<span class="hlt">DAR</span> to capture the landscape state before and after unique hydrologic events such as: low-intensity rain storms, winter snowmelt, and summer convective thunderstorms. Comparing the landscape topography before and after</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li class="active"><span>16</span></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_16 --> <div id="page_17" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li class="active"><span>17</span></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="321"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016SPIE.9901E..0XD','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016SPIE.9901E..0XD"><span id="translatedtitle">An automatic and overlap based method for Li<span class="hlt">DAR</span> intensity correction</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Ding, Qiong</p> <p>2016-03-01</p> <p>Li<span class="hlt">DAR</span> provides intensity data that reflect the material characteristics of objects. However, intensity values need to be corrected before they can be reliably used for applications because of the error during data acquisition. This study proposed an automatic and overlap based method for intensity correction. Firstly, a radar equation based method was employed for removal of main errors. Then, nearest neighbor algorithm was used to find out homologous points of overlap regions and assumption was made that homologous points should have same intensity. Finally, an improved model was utilized to eliminate overlap discrepancies. This method can be considered as a potential aid to enhance the accuracy of Li<span class="hlt">DAR</span> intensity data and improve the automation of data process.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2009EGUGA..1110421K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2009EGUGA..1110421K"><span id="translatedtitle">Characterization of Forest Ecosystems by combined Radiative Transfer Modeling for Imaging Spectrometer and Li<span class="hlt">DAR</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Koetz, B.; Sun, G.; Morsdorf, F.; Rubio, J.; Kimes, D.; Ranson, J.</p> <p>2009-04-01</p> <p>This research was motivated by the increased information dimensionality provided by current Earth Observation systems measuring the complex and dynamic medium of the vegetated surface of the Earth. Advanced and reliable algorithms that fully exploit this enhanced Earth Observation information are needed to deliver consistent data sets of the Earth vegetation condition describing its spatial distribution and change over time. Spectral observation provided by imaging spectrometers and the waveform from large-footprint Li<span class="hlt">DAR</span> are now available from space for forest ecosystem studies. The imaging spectrometer data contains information about the biochemical composition of the canopy foliage, and is widely used to estimate biophysical canopy parameters such as LAI and fractional cover. Li<span class="hlt">DAR</span> responds to the vertical distribution of scatters and permits inferences about the plant structures required to supply water and mechanical support to those surfaces. Various canopy height indices derived from Li<span class="hlt">DAR</span> waveform have been successfully used to infer forest above-ground biomass and the characterization of canopy structure. The structure parameters derived from Li<span class="hlt">DAR</span> data can improve the accuracy and robustness of canopy parameter retrieval from imaging spectrometer by reducing uncertainties related to the canopy structure. The specific information content, inherent to the observations of imaging spectrometry and LIDAR, assesses thus different but complementary characteristics of the complex vegetation canopy. The combination of these two information dimensions offers a unique and reliable canopy characterization including information relevant to different aspects of the biochemical and biophysical properties and thus understanding of processes within forest ecosystems. A comprehensive canopy characterization of a forest ecosystem is derived from the combined remote sensing signal of imaging spectrometry and large footprint LIDAR. The inversion of two linked physically based</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/25457158','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/25457158"><span id="translatedtitle">Advances in animal ecology from 3D-Li<span class="hlt">DAR</span> ecosystem mapping.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Davies, Andrew B; Asner, Gregory P</p> <p>2014-12-01</p> <p>The advent and recent advances of Light Detection and Ranging (Li<span class="hlt">DAR</span>) have enabled accurate measurement of 3D ecosystem structure. Here, we review insights gained through the application of Li<span class="hlt">DAR</span> to animal ecology studies, revealing the fundamental importance of structure for animals. Structural heterogeneity is most conducive to increased animal richness and abundance, and increased complexity of vertical vegetation structure is more positively influential compared with traditionally measured canopy cover, which produces mixed results. However, different taxonomic groups interact with a variety of 3D canopy traits and some groups with 3D topography. To develop a better understanding of animal dynamics, future studies will benefit from considering 3D habitat effects in a wider variety of ecosystems and with more taxa. PMID:25457158</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015PhDT.......176S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015PhDT.......176S"><span id="translatedtitle">Remote sensing based detection of forested wetlands: An evaluation of Li<span class="hlt">DAR</span>, aerial imagery, and their data fusion</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Suiter, Ashley Elizabeth</p> <p></p> <p>Multi-spectral imagery provides a robust and low-cost dataset for assessing wetland extent and quality over broad regions and is frequently used for wetland inventories. However in forested wetlands, hydrology is obscured by tree canopy making it difficult to detect with multi-spectral imagery alone. Because of this, classification of forested wetlands often includes greater errors than that of other wetlands types. Elevation and terrain derivatives have been shown to be useful for modelling wetland hydrology. But, few studies have addressed the use of Li<span class="hlt">DAR</span> intensity data detecting hydrology in forested wetlands. Due the tendency of Li<span class="hlt">DAR</span> signal to be attenuated by water, this research proposed the fusion of Li<span class="hlt">DAR</span> intensity data with Li<span class="hlt">DAR</span> elevation, terrain data, and aerial imagery, for the detection of forested wetland hydrology. We examined the utility of Li<span class="hlt">DAR</span> intensity data and determined whether the fusion of Lidar derived data with multispectral imagery increased the accuracy of forested wetland classification compared with a classification performed with only multi-spectral image. Four classifications were performed: Classification A -- All Imagery, Classification B -- All Li<span class="hlt">DAR</span>, Classification C -- Li<span class="hlt">DAR</span> without Intensity, and Classification D -- Fusion of All Data. These classifications were performed using random forest and each resulted in a 3-foot resolution thematic raster of forested upland and forested wetland locations in Vermilion County, Illinois. The accuracies of these classifications were compared using Kappa Coefficient of Agreement. Importance statistics produced within the random forest classifier were evaluated in order to understand the contribution of individual datasets. Classification D, which used the fusion of Li<span class="hlt">DAR</span> and multi-spectral imagery as input variables, had moderate to strong agreement between reference data and classification results. It was found that Classification A performed using all the Li<span class="hlt">DAR</span> data and its derivatives</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20050156907','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20050156907"><span id="translatedtitle">Mapping and Monitoring Delmarva Fox Squirrel Habitat Using an Airborne Li<span class="hlt">DAR</span> Profiler</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Nelson, Ross; Ratnaswamy, Mary; Keller, Cherry</p> <p>2004-01-01</p> <p>Twenty five hundred thirty nine kilometers of airborne laser profiling and videography data were acquired over the state of Delaware during the summer of 2000. The laser ranging measurements and video from approximately one-half of that data set (1304 km) were analyzed to identify and locate forested sites that might potentially support populations of Delmarva fox squirrel (DFS, Sciurus niger cinereus). The DFS is an endangered species previously endemic to tall, dense, mature forests with open understories on the Eastern Shore of the Chesapeake Bay. The airborne Li<span class="hlt">DAR</span> employed in this study can measure forest canopy height and canopy closure, but cannot measure or infer understory canopy conditions. Hence the Li<span class="hlt">DAR</span> must be viewed as a tool to map potential, not actual, habitat. Fifty-three potentially suitable DFS sites were identified in the 1304 km of flight transect data. Each of the 53 sites met the following criteria according to the Li<span class="hlt">DAR</span> and video record: (1 ) at least 120m of contiguous forest; (2) an average canopy height greater than 20m; (3) an average canopy closure of >80%; and (4) no roofs, impervious surface (e.g., asphalt, concrete), and/or open water anywhere along the 120m length of the laser segment. Thirty-two of the 53 sites were visited on the ground and measurements taken for a DFS habitat suitability model. Seventy eight percent of the sites (25 of 32) were judged by the model to be suited to supporting a DFS population. Twenty-eight of the 32 sites visited in the field were in forest cover types (hardwood, mixed wood, conifer, wetlands) according to a land cover GIS map. Of these, 23 (82%) were suited to support DFS. The remaining 4 sites were located in nonforest cover types - agricultural or residential areas. Two of the four, or 50% were suited to the DFS. All of the Li<span class="hlt">DAR</span> flight data, 2539 km, were analyzed to</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2015AGUFM.B43C0584S&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2015AGUFM.B43C0584S&link_type=ABSTRACT"><span id="translatedtitle">Flying Under the Li<span class="hlt">DAR</span>: Relating Forest Structure to Bat Community Diversity</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Swanson, A. C.; Weishampel, J. F.</p> <p>2015-12-01</p> <p>Bats are important to many ecological processes such as pollination, insect (and by proxy, disease) control, and seed dispersal and can be used to monitor ecosystem health. However, they are facing unprecedented extinction risks from habitat degradation as well as pressures from pathogens (e.g., white-nose syndrome) and wind turbines. Li<span class="hlt">DAR</span> allows ecologists to measure structural variables of forested landscapes with increased precision and accuracy at broader spatial scales than previously possible. This study used airborne Li<span class="hlt">DAR</span> to classify forest habitat/canopy structure at the Ordway-Swisher Biological Station (OSBS) in north central Florida. Li<span class="hlt">DAR</span> data were acquired by the NEON airborne observation platform in summer 2014. OSBS consists of open-canopy pine savannas, closed-canopy hardwood hammocks, and seasonally wet prairies. Multiple forest structural parameters (e.g., mean, maximum, and standard deviation of height returns) were derived from Li<span class="hlt">DAR</span> point clouds using the USDA software program FUSION. K-means clustering was used to segregate each 5x5 m raster across the ~3765 ha OSBS area into six different clusters based on the derived canopy metrics. Cluster averages for maximum, mean, and standard deviation of return heights ranged from 0 to 19.4 m, 0 to 15.3 m, and 0 to 3.0 m, respectively. To determine the relationships among these landscape-canopy features and bat species diversity and abundances, AnaBat II bat detectors were deployed from May to September in 2015 stratified by these distinct clusters. Bat calls were recorded from sunset to sunrise during each sampling period. Species were identified using AnalookW. A statistical regression model selection approach was performed in order to evaluate how forest attributes such as understory clutter, open regions, open and closed canopy, etc. influence bat communities. This knowledge provides a deeper understanding of habitat-species interactions to better manage survival of these species.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2012AGUFM.V21B2779C&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2012AGUFM.V21B2779C&link_type=ABSTRACT"><span id="translatedtitle">Topographic and Thermal Investigations of Active Pahoehoe Lava Flows Using Coupled Li<span class="hlt">DAR</span>/FLIR Datasets</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Crown, D. A.; Anderson, S. W.; Finnegan, D. C.; LeWinter, A. L.; Ramsey, M.</p> <p>2012-12-01</p> <p>Pahoehoe lava flows consist of multiple overlapping and interfingering lobes and exhibit morphologically diverse surfaces characterized by channels, smooth-surfaced sheets, and numerous, small networks of interconnected pahoehoe toes. In order to analyze the different pahoehoe emplacement regimes, we have acquired simultaneous high-resolution topographic and thermal measurements of advancing and inflating flow lobes at high temporal frequency. These datasets allow the creation of flow lobe maps at regular intervals during flow emplacement that document morphologic, thermal, and morphometric characteristics of individual pahoehoe elements (e.g., pahoehoe toes) as well as compound pahoehoe features (e.g., toe networks, channels with lateral levees). These datasets reveal patterns in flow behavior and provide quantitative documentation of flow emplacement processes. Field investigations were conducted in February and March, 2012 on tube-fed pahoehoe flows in the Puu Oo flow field, Kilauea Volcano, Hawaii. We utilized a ground-based, full-waveform scanning Li<span class="hlt">DAR</span> and FLIR SC645 thermal infrared camera, supplemented by high-definition video and time-lapse photography. The Li<span class="hlt">DAR</span> scanner is capable of acquiring rapid, successive scans with reproducible 5 mm resolution data at a rate of 300 kHz. The FLIR camera acquires calibrated thermal images in the 7.5 - 13 mm range; the object temperature range is -20°C to +2000°C, with a thermal sensitivity of <0.05°C at 30°C. An RTK GPS was used to acquire precise locations of scan positions and to georeference Li<span class="hlt">DAR</span> point cloud data to real-world coordinates. The combined Li<span class="hlt">DAR</span>/FLIR system provides rapid acquisition of high-resolution spatial and high-precision thermal datasets for advancing pahoehoe flows.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20150023286','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20150023286"><span id="translatedtitle">NASA Goddards Li<span class="hlt">DAR</span>, Hyperspectral and Thermal (G-LiHT) Airborne Imager</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Cook, Bruce D.; Corp, Lawrence A.; Nelson, Ross F.; Middleton, Elizabeth M.; Morton, Douglas C.; McCorkel, Joel T.; Masek, Jeffrey G.; Ranson, Kenneth J.; Ly, Vuong; Montesano, Paul M.</p> <p>2013-01-01</p> <p>The combination of Li<span class="hlt">DAR</span> and optical remotely sensed data provides unique information about ecosystem structure and function. Here, we describe the development, validation and application of a new airborne system that integrates commercial off the shelf Li<span class="hlt">DAR</span> hyperspectral and thermal components in a compact, lightweight and portable system. Goddard's Li<span class="hlt">DAR</span>, Hyperspectral and Thermal (G-LiHT) airborne imager is a unique system that permits simultaneous measurements of vegetation structure, foliar spectra and surface temperatures at very high spatial resolution (approximately 1 m) on a wide range of airborne platforms. The complementary nature of Li<span class="hlt">DAR</span>, optical and thermal data provide an analytical framework for the development of new algorithms to map plant species composition, plant functional types, biodiversity, biomass and carbon stocks, and plant growth. In addition, G-LiHT data enhance our ability to validate data from existing satellite missions and support NASA Earth Science research. G-LiHT's data processing and distribution system is designed to give scientists open access to both low- and high-level data products (http://gliht.gsfc.nasa.gov), which will stimulate the community development of synergistic data fusion algorithms. G-LiHT has been used to collect more than 6,500 km2 of data for NASA-sponsored studies across a broad range of ecoregions in the USA and Mexico. In this paper, we document G-LiHT design considerations, physical specifications, instrument performance and calibration and acquisition parameters. In addition, we describe the data processing system and higher-level data products that are freely distributed under NASA's Data and Information policy.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012SPIE.8537E..0MW','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012SPIE.8537E..0MW"><span id="translatedtitle">Reduction of training costs using active classification in fused hyperspectral and Li<span class="hlt">DAR</span> data</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Wuttke, Sebastian; Schilling, Hendrik; Middelmann, Wolfgang</p> <p>2012-11-01</p> <p>This paper presents a novel approach for the reduction of training costs in classification with co-registered hyperspectral (HS) and Light Detection and Ranging (Li<span class="hlt">DAR</span>) data using an active classification framework. Fully automatic classification can be achieved by unsupervised learning, which is not suited for adjustment to specific classes. On the other hand, supervised classification with predefined classes needs a lot of training examples, which need to be labeled with the ground truth, usually at a significant cost. The concept of active classification alleviates these problems by the use of a selection strategy: only selected samples are ground truth labeled and used as training data. One common selection strategy is to incorporate in a first step the current state of the classification algorithm and choose only the examples for which the expected information gain is maximized. In the second step a conventional classification algorithm is trained using this data. By alternating between these two steps the algorithm reaches high classification accuracy results with less training samples and therefore lower training costs. The approach presented in this paper involves the user in the active selection strategy and the k-NN algorithm is chosen for classification. The results further benefit from fusing the heterogeneous information of HS and Li<span class="hlt">DAR</span> data within the classification algorithm. For this purpose, several HS features, such as vegetation indices, and Li<span class="hlt">DAR</span> features, such as relative height and roughness, are extracted. This increases the separability between different classes and reduces the dimensionality of the HS data. The practicability and performance of this framework is shown for the detection and separation of different kinds of vegetation, e.g. trees and grass in an urban area of Berlin. The HS data was obtained by the SPECIM AISA Eagle 2 sensor, Li<span class="hlt">DAR</span> data by Riegl LMS Q560.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://pubs.er.usgs.gov/publication/70175910','USGSPUBS'); return false;" href="http://pubs.er.usgs.gov/publication/70175910"><span id="translatedtitle">Quantitative study of tectonic geomorphology along Haiyuan fault based on airborne Li<span class="hlt">DAR</span></span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Chen, Tao; Zhang, Pei Zhen; Liu, Jing; Li, Chuan You; Ren, Zhi Kun; Hudnut, Kenneth W.</p> <p>2014-01-01</p> <p>High-precision and high-resolution topography are the fundamental data for active fault research. Light detection and ranging (Li<span class="hlt">DAR</span>) presents a new approach to build detailed digital elevation models effectively. We take the Haiyuan fault in Gansu Province as an example of how Li<span class="hlt">DAR</span> data may be used to improve the study of active faults and the risk assessment of related hazards. In the eastern segment of the Haiyuan fault, the Shaomayin site has been comprehensively investigated in previous research because of its exemplary tectonic topographic features. Based on unprecedented Li<span class="hlt">DAR</span> data, the horizontal and vertical coseismic offsets at the Shaomayin site are described. The measured horizontal value is about 8.6 m, and the vertical value is about 0.8 m. Using prior dating ages sampled from the same location, we estimate the horizontal slip rate as 4.0 ± 1.0 mm/a with high confidence and define that the lower bound of the vertical slip rate is 0.4 ± 0.1 mm/a since the Holocene. Li<span class="hlt">DAR</span> data can repeat the measurements of field work on quantifying offsets of tectonic landform features quite well. The offset landforms are visualized on an office computer workstation easily, and specialized software may be used to obtain displacement quantitatively. By combining precious chronological results, the fundamental link between fault activity and large earthquakes is better recognized, as well as the potential risk for future earthquake hazards.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015AGUFM.B43C0549W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015AGUFM.B43C0549W"><span id="translatedtitle">Mapping Vegetation Canopy Structure and Distribution for Great Smoky Mountains National Park Using Li<span class="hlt">DAR</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Wu, Z.; Weiner, J.; Kumar, J.; Norman, S. P.; Hargrove, W. W.; Collier, N.; Hoffman, F. M.</p> <p>2015-12-01</p> <p>A major challenge in forest management is the inaccessibility of large swaths of land, which makes accurate monitoring of forest change difficult. Remote sensing methods can help address this issue by allowing investigators to monitor remote or inaccessible regions using aerial or satellite-based platforms. However, most remote sensing methods do not provide a full three-dimensional (3D) description of the area. Rather, they return only a single elevation point or landcover description. Multiple-return Li<span class="hlt">DAR</span> (Light Detection and Ranging) gathers data in a 3D point cloud, which allows forest managers to more accurately characterize and monitor changes in canopy structure and vegetation-type distribution. Our project used high-resolution aerial multiple-return Li<span class="hlt">DAR</span> data to determine vegetation canopy structures and their spatial distribution in Great Smoky Mountains National Park. To ensure sufficient data density and to match LANDSAT resolution, we gridded the data into 30m x 30m cells. The Li<span class="hlt">DAR</span> data points within each cell were then used to generate the vertical canopy structure for that cell. After vertical profiles had been created, we used a k-means cluster analysis algorithm to classify the landscape based on the canopy structure. The spatial distribution of distinct and unique canopy structures was mapped across the park and compared to a vegetation-type map to determine the correlation of canopy structure to vegetation types. Preliminary analysis conducted at a number of phenology sites maintained by the Great Smoky Mountains Institute at Tremont shows strong correspondence between canopy structure and vegetation type. However, more validation is needed in other regions of the park to establish this method as a reliable tool. Li<span class="hlt">DAR</span> data has a unique ability to map full 3D structures of vegetation and the methods developed in this project offer an extensible tool for forest mapping and monitoring.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://pubs.er.usgs.gov/publication/70042983','USGSPUBS'); return false;" href="http://pubs.er.usgs.gov/publication/70042983"><span id="translatedtitle">Strategies for minimizing sample size for use in airborne Li<span class="hlt">DAR</span>-based forest inventory</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Junttila, Virpi; Finley, Andrew O.; Bradford, John B.; Kauranne, Tuomo</p> <p>2013-01-01</p> <p>Recently airborne Light Detection And Ranging (Li<span class="hlt">DAR</span>) has emerged as a highly accurate remote sensing modality to be used in operational scale forest inventories. Inventories conducted with the help of Li<span class="hlt">DAR</span> are most often model-based, i.e. they use variables derived from Li<span class="hlt">DAR</span> point clouds as the predictive variables that are to be calibrated using field plots. The measurement of the necessary field plots is a time-consuming and statistically sensitive process. Because of this, current practice often presumes hundreds of plots to be collected. But since these plots are only used to calibrate regression models, it should be possible to minimize the number of plots needed by carefully selecting the plots to be measured. In the current study, we compare several systematic and random methods for calibration plot selection, with the specific aim that they be used in Li<span class="hlt">DAR</span> based regression models for forest parameters, especially above-ground biomass. The primary criteria compared are based on both spatial representativity as well as on their coverage of the variability of the forest features measured. In the former case, it is important also to take into account spatial auto-correlation between the plots. The results indicate that choosing the plots in a way that ensures ample coverage of both spatial and feature space variability improves the performance of the corresponding models, and that adequate coverage of the variability in the feature space is the most important condition that should be met by the set of plots collected.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2012SPIE.8538E..0IK&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2012SPIE.8538E..0IK&link_type=ABSTRACT"><span id="translatedtitle">3D campus modeling using Li<span class="hlt">DAR</span> point cloud data</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kawata, Yoshiyuki; Yoshii, Satoshi; Funatsu, Yukihiro; Takemata, Kazuya</p> <p>2012-10-01</p> <p>The importance of having a 3D urban city model is recognized in many applications, such as management offices of risk and disaster, the offices for city planning and developing and others. As an example of urban model, we reconstructed 3D KIT campus manually in this study, by utilizing airborne Li<span class="hlt">DAR</span> point cloud data. The automatic extraction of building shapes was left in future work.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2004CG.....30..345Z&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2004CG.....30..345Z&link_type=ABSTRACT"><span id="translatedtitle">Urban 3D GIS From Li<span class="hlt">DAR</span> and digital aerial images</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Zhou, Guoqing; Song, C.; Simmers, J.; Cheng, P.</p> <p>2004-05-01</p> <p>This paper presents a method, which integrates image knowledge and Light Detection And Ranging (Li<span class="hlt">DAR</span>) point cloud data for urban digital terrain model (DTM) and digital building model (DBM) generation. The DBM is an Object-Oriented data structure, in which each building is considered as a building object, i.e., an entity of the building class. The attributes of each building include roof types, polygons of the roof surfaces, height, parameters describing the roof surfaces, and the Li<span class="hlt">DAR</span> point array within the roof surfaces. Each polygon represents a roof surface of building. This type of data structure is flexible for adding other building attributes in future, such as texture information and wall information. Using image knowledge extracted, we developed a new method of interpolating Li<span class="hlt">DAR</span> raw data into grid digital surface model (DSM) with considering the steep discontinuities of buildings. In this interpolation method, the Li<span class="hlt">DAR</span> data points, which are located in the polygon of roof surfaces, first are determined, and then interpolation via planar equation is employed for grid DSM generation. The basic steps of our research are: (1) edge detection by digital image processing algorithms; (2) complete extraction of the building roof edges by digital image processing and human-computer interactive operation; (3) establishment of DBM; (4) generation of DTM by removing surface objects. Finally, we implement the above functions by MS VC++ programming. The outcome of urban 3D DSM, DTM and DBM is exported into urban database for urban 3D GIS.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2012AGUFM.V21B2780L&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2012AGUFM.V21B2780L&link_type=ABSTRACT"><span id="translatedtitle">Characterizing active volcanic processes at Kilauea volcano using Li<span class="hlt">DAR</span> scanning</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>LeWinter, A. L.; Finnegan, D. C.; Patrick, M. R.; Anderson, S. W.; Orr, T. R.</p> <p>2012-12-01</p> <p>Active craters and lava lakes evolve in response to a variety of volcanic processes. Quantifying those changes can be difficult or even impossible, for safety reasons, due to the technical limitations of sensors that require a minimum standoff distance. In recent years, advancements in ground-based Light Detection and Ranging (Li<span class="hlt">DAR</span>) scanners and accessibility to these systems have enhanced our ability to capture data in a diversity of volcanic settings at the highest spatial and temporal resolutions yet seen. Moreover, advancements in full-waveform digitization have significantly improved the ability to acquire data in environments where ash, steam, and sulfur dioxide emissions have historically hampered efforts. Kilauea's ongoing summit eruption, which began in March 2008, has been characterized in part by the evolution of its vent into a 160-meter diameter collapse crater holding an active lava lake. This process has been documented in detail by field and webcam observations, but has not been accurately quantified. Our research focuses on acquiring repeat, high-resolution full-waveform Li<span class="hlt">DAR</span> data throughout 2012 to monitor changes in the geometry of Kilauea's active lava lake and the crater to which it is confined. We collected Li<span class="hlt">DAR</span> data in February and July 2012, with plans for an additional survey in October 2012. Our results show changes in the shape of the vent walls and the shape and level of the confined lava lake. Specifically, the Li<span class="hlt">DAR</span> data has revealed 1) changes in the lava lake level, corresponding to tiltmeter observations of pressure fluctuations in the summit magma reservoir, 2) enlargement of the vent cavity, due to frequent rock falls, and 3) modifications to the lake size and surrounding lava ledges due to competing processes of accretion and collapse. The rapid acquisition of repeat, high-resolution topographic data enables researchers to more accurately characterize shape and volume changes involved in a range of eruptive systems, while</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2016JPRS..118...22H&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2016JPRS..118...22H&link_type=ABSTRACT"><span id="translatedtitle">Road centerline extraction from airborne Li<span class="hlt">DAR</span> point cloud based on hierarchical fusion and optimization</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Hui, Zhenyang; Hu, Youjian; Jin, Shuanggen; Yevenyo, Yao Ziggah</p> <p>2016-08-01</p> <p>Road information acquisition is an important part of city informatization construction. Airborne Li<span class="hlt">DAR</span> provides a new means of acquiring road information. However, the existing road extraction methods using Li<span class="hlt">DAR</span> point clouds always decide the road intensity threshold based on experience, which cannot obtain the optimal threshold to extract a road point cloud. Moreover, these existing methods are deficient in removing the interference of narrow roads and several attached areas (e.g., parking lot and bare ground) to main roads extraction, thereby imparting low completeness and correctness to the city road network extraction result. Aiming at resolving the key technical issues of road extraction from airborne Li<span class="hlt">DAR</span> point clouds, this paper proposes a novel method to extract road centerlines from airborne Li<span class="hlt">DAR</span> point clouds. The proposed approach is mainly composed of three key algorithms, namely, Skewness balancing, Rotating neighborhood, and Hierarchical fusion and optimization (SRH). The skewness balancing algorithm used for the filtering was adopted as a new method for obtaining an optimal intensity threshold such that the "pure" road point cloud can be obtained. The rotating neighborhood algorithm on the other hand was developed to remove narrow roads (corridors leading to parking lots or sidewalks), which are not the main roads to be extracted. The proposed hierarchical fusion and optimization algorithm caused the road centerlines to be unaffected by certain attached areas and ensured the road integrity as much as possible. The proposed method was tested using the Vaihingen dataset. The results demonstrated that the proposed method can effectively extract road centerlines in a complex urban environment with 91.4% correctness and 80.4% completeness.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016EGUGA..18.3829A','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016EGUGA..18.3829A"><span id="translatedtitle">Abu Dhabi Basemap Update Using the Li<span class="hlt">DAR</span> Mobile Mapping Technology</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Alshaiba, Omar; Amparo Núñez-Andrés, M.; Lantada, Nieves</p> <p>2016-04-01</p> <p>Mobile Li<span class="hlt">DAR</span> system provides a new technology which can be used to update geospatial information by direct and rapid data collection. This technology is faster than the traditional survey ways and has lower cost. Abu Dhabi Municipal System aims to update its geospatial system frequently as the government entities have invested heavily in GIS technology and geospatial data to meet the repaid growth in the infrastructure and construction projects in recent years. The Emirate of Abu Dhabi has witnessed a huge growth in infrastructure and construction projects in recent years. Therefore, it is necessary to develop and update its basemap system frequently to meet their own organizational needs. Currently, the traditional ways are used to update basemap system such as human surveyors, GPS receivers and controller (GPS assigned computer). Then the surveyed data are downloaded, edited and reviewed manually before it is merged to the basemap system. Traditional surveying ways may not be applicable in some conditions such as; bad weather, difficult topographic area and boundary area. This paper presents a proposed methodology which uses the Mobile Li<span class="hlt">DAR</span> system to update basemap in Abu Dhabi by using daily transactions services. It aims to use and integrate the mobile Li<span class="hlt">DAR</span> technology into the municipality's daily workflow such that it becomes the new standard cost efficiency operating procedure for updating the base-map in Abu Dhabi Municipal System. On another note, the paper will demonstrate the results of the innovated workflow for the base-map update using the mobile Li<span class="hlt">DAR</span> point cloud and few processing algorithms.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2009SPIE.7460E..07B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2009SPIE.7460E..07B"><span id="translatedtitle">Skeleton-based botanic tree diameter estimation from dense Li<span class="hlt">DAR</span> data</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Bucksch, Alexander; Lindenbergh, Roderik; Menenti, Massimo; Rahman, Muhammad Z.</p> <p>2009-08-01</p> <p>New airborne Li<span class="hlt">DAR</span> (Light Detection and Ranging) measurement systems, like the FLI-MAP 400 System, make it possible to obtain high density data containing far more information about single objects, like trees, than traditional airborne laser systems. Therefore, it becomes feasible to analyze geometric properties of trees on the individual object level. In this paper a new 3-step strategy is presented to calculate the stem diameter of individual natural trees at 1.3m height, the so-called breast height diameter, which is an important parameter for forest inventory and flooding simulations. Currently, breast height diameter estimates are not obtained from direct measurements, but are derived using species dependent allometric constraints. Our strategy involves three independent steps: 1. Delineation of the individual trees as represented by the Li<span class="hlt">DAR</span> data, 2. Skeletonization of the single trees, and 3. Determination of the breast height diameter computing the distance of a suited subset of Li<span class="hlt">DAR</span> points to the local skeleton. The use of a recently developed skeletonization algorithm based on graph-reduction is the key to the breast height measurement. A set of four relevant test cases is presented and validated against hand measurements. It is shown that the new 3-step approach automatically derives breast height diameters deviating only 10% from hand measurements in four test cases. The potential of the introduced method in practice is demonstrated on the fully automatic analysis of a Li<span class="hlt">DAR</span> data set representing a patch of forest consisting of 49 individual trees.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014AGUFM.B51B0022M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014AGUFM.B51B0022M"><span id="translatedtitle">Single Pass Li<span class="hlt">DAR</span>-derived Estimate of Site Productivity in Western Oregon</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>McAdam, E.; Hilker, T.; Waring, R. H.; Sousa, C. H. R. D.; Moura, Y. M.</p> <p>2014-12-01</p> <p>Accurate estimates of forest growth at different ages are essential to evaluate the effect of a changing climate and to adjust management practices accordingly. Most current approaches are spatially discrete and therefore unable to predict forest growth accurately across landscapes. While airborne Li<span class="hlt">DAR</span> has been widely used in forestry, it can only estimate growth rates with repeated passes. In contrast, Landsat imagery records disturbances (at 30 m resolution) but is unable to measure changes in growth rates. Historical archives of Landsat imagery provided us a way of knowing when and where even-aged stands of Pseudotsuga menziesii (Douglas-fir) were cut and replanted. Since early growth rates are nearly linear with age, the height of dominant trees recorded in one pass by Li<span class="hlt">DAR</span> yields a direct measure of growth and likely changes as stands age under recent climatic conditions. Process-based growth models are available to assess possible shifts in the growth rates of stands under a changing climate; the accuracy of such model predictions can be evaluated with additional Li<span class="hlt">DAR</span> coverage. In this study we use the Physiological Principles Predicting Growth Model (3-PG) to estimate site index at the landscape level to predict site productivity based on the year of stand establishment obtained from Landsat, and one-pass airborne Li<span class="hlt">DAR</span> measurement of forest height. We are monitoring forest plantations of known ages and with data on their current age we will calculate site index for 60 separate sites across western Oregon. The results of this study will allow us to create updated site index maps for the state of Oregon under varying climate scenarios.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014AGUFMNH41B3785M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014AGUFMNH41B3785M"><span id="translatedtitle">Evaluation of Landslide Mapping Techniques and Li<span class="hlt">DAR</span>-based Conditioning Factors</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Mahalingam, R.; Olsen, M. J.</p> <p>2014-12-01</p> <p>Landslides are a major geohazard, which result in significant human, infrastructure, and economic losses. Landslide susceptibility mapping can help communities to plan and prepare for these damaging events. Mapping landslide susceptible locations using GIS and remote sensing techniques is gaining popularity in the past three decades. These efforts use a wide variety of procedures and consider a wide range of factors. Unfortunately, each study is often completed differently and independently of others. Further, the quality of the datasets used varies in terms of source, data collection, and generation, which can propagate errors or inconsistencies into the resulting output maps. Light detection and ranging (Li<span class="hlt">DAR</span>) has proved to have higher accuracy in representing the continuous topographic surface, which can help minimize this uncertainty. The primary objectives of this paper are to investigate the applicability and performance of terrain factors in landslide hazard mapping, determine if Li<span class="hlt">DAR</span>-derived datasets (slope, slope roughness, terrain roughness, stream power index and compound topographic index) can be used for predictive mapping without data representing other common landslide conditioning factors, and evaluate the differences in landslide susceptibility mapping using widely-used statistical approaches. The aforementioned factors were used to produce landslide susceptibility maps for a 140 km2 study area in northwest Oregon using six representative techniques: frequency ratio, weights of evidence, logistic regression, discriminant analysis, artificial neural network, and support vector machine. Most notably, the research showed an advantage in selecting fewer critical conditioning factors. The most reliable factors all could be derived from a single Li<span class="hlt">DAR</span> DEM, reducing the need for laborious and costly data gathering. Most of the six techniques showed similar statistical results; however, ANN showed less accuracy for predictive mapping. Keywords : Li<span class="hlt">DAR</span></p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li class="active"><span>17</span></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_17 --> <div id="page_18" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li class="active"><span>18</span></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="341"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=20090027836&hterms=58&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3D0.58','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=20090027836&hterms=58&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3D0.58"><span id="translatedtitle">Estimating Volume, Biomass, and Carbon in Hedmark County, Norway Using a Profiling Li<span class="hlt">DAR</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Nelson, Ross; Naesset, Erik; Gobakken, T.; Gregoire, T.; Stahl, G.</p> <p>2009-01-01</p> <p>A profiling airborne Li<span class="hlt">DAR</span> is used to estimate the forest resources of Hedmark County, Norway, a 27390 square kilometer area in southeastern Norway on the Swedish border. One hundred five profiling flight lines totaling 9166 km were flown over the entire county; east-west. The lines, spaced 3 km apart north-south, duplicate the systematic pattern of the Norwegian Forest Inventory (NFI) ground plot arrangement, enabling the profiler to transit 1290 circular, 250 square meter fixed-area NFI ground plots while collecting the systematic Li<span class="hlt">DAR</span> sample. Seven hundred sixty-three plots of the 1290 plots were overflown within 17.8 m of plot center. Laser measurements of canopy height and crown density are extracted along fixed-length, 17.8 m segments closest to the center of the ground plot and related to basal area, timber volume and above- and belowground dry biomass. Linear, nonstratified equations that estimate ground-measured total aboveground dry biomass report an R(sup 2) = 0.63, with an regression RMSE = 35.2 t/ha. Nonstratified model results for the other biomass components, volume, and basal area are similar, with R(sup 2) values for all models ranging from 0.58 (belowground biomass, RMSE = 8.6 t/ha) to 0.63. Consistently, the most useful single profiling Li<span class="hlt">DAR</span> variable is quadratic mean canopy height, h (sup bar)(sub qa). Two-variable models typically include h (sup bar)(sub qa) or mean canopy height, h(sup bar)(sub a), with a canopy density or a canopy height standard deviation measure. Stratification by productivity class did not improve the nonstratified models, nor did stratification by pine/spruce/hardwood. County-wide profiling Li<span class="hlt">DAR</span> estimates are reported, by land cover type, and compared to NFI estimates.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014AGUFM.H11M..05H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014AGUFM.H11M..05H"><span id="translatedtitle">Utilizing Li<span class="hlt">DAR</span> Datasets From Experimental Watersheds to Advance Ecohydrological Understanding in Seasonally Snow-Covered Forests</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Harpold, A. A.; Broxton, P. D.; Guo, Q.; Barlage, M. J.; Gochis, D. J.</p> <p>2014-12-01</p> <p>The Western U.S. is strongly reliant on snowmelt from forested areas for ecosystem services and downstream populations. The ability to manage water resources from snow-covered forests faces major challenges from drought, disturbance, and regional changes in climate. An exciting avenue for improving ecohydrological process understanding is Light Detection and Ranging (Li<span class="hlt">DAR</span>) because the technology simultaneously observes topography, forest properties, and snow/ice at high-resolution (<10 cm) and over large extents (>100 km2). The availability and quality of Li<span class="hlt">DAR</span> datasets is increasing rapidly, however they remain under-utilized for process-based ecohydrology investigations. This presentation will illustrate how Li<span class="hlt">DAR</span> datasets from the Critical Zone Observatory (CZO) network have been applied to advance ecohydrological understanding through direct empirical analysis, as well as model parameterization and verification. Direct analysis of the datasets has proved fruitful for pre- and post-disturbance snow distribution estimates and interpreting in-situ snow depth measurements across sites. In addition, we illustrate the potential value of Li<span class="hlt">DAR</span> to parameterize and verify of physical models with two examples. First, we use Li<span class="hlt">DAR</span> to parameterize a land surface model, Noah multi-parameterization (Noah-MP), to investigate the sensitivity of modeled water and energy fluxes to high-resolution forest information. Second, we present a Snow Physics and Laser Mapping (SnowPALM) model that is parameterized with Li<span class="hlt">DAR</span> information at its native 1-m scale. Both modeling studies demonstrate the value of Li<span class="hlt">DAR</span> for representing processes with greater fidelity. More importantly, the increased model fidelity led to different estimates of water and energy fluxes at larger, watershed scales. Creating a network of experimental watersheds with Li<span class="hlt">DAR</span> datasets offers the potential to test theories and models in previously unexplored ways.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/27410085','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/27410085"><span id="translatedtitle">Effects of Li<span class="hlt">DAR</span> point density, sampling size and height threshold on estimation accuracy of crop biophysical parameters.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Luo, Shezhou; Chen, Jing M; Wang, Cheng; Xi, Xiaohuan; Zeng, Hongcheng; Peng, Dailiang; Li, Dong</p> <p>2016-05-30</p> <p>Vegetation leaf area index (LAI), height, and aboveground biomass are key biophysical parameters. Corn is an important and globally distributed crop, and reliable estimations of these parameters are essential for corn yield forecasting, health monitoring and ecosystem modeling. Light Detection and Ranging (Li<span class="hlt">DAR</span>) is considered an effective technology for estimating vegetation biophysical parameters. However, the estimation accuracies of these parameters are affected by multiple factors. In this study, we first estimated corn LAI, height and biomass (R<sup>2</sup> = 0.80, 0.874 and 0.838, respectively) using the original Li<span class="hlt">DAR</span> data (7.32 points/m<sup>2</sup>), and the results showed that Li<span class="hlt">DAR</span> data could accurately estimate these biophysical parameters. Second, comprehensive research was conducted on the effects of Li<span class="hlt">DAR</span> point density, sampling size and height threshold on the estimation accuracy of LAI, height and biomass. Our findings indicated that Li<span class="hlt">DAR</span> point density had an important effect on the estimation accuracy for vegetation biophysical parameters, however, high point density did not always produce highly accurate estimates, and reduced point density could deliver reasonable estimation results. Furthermore, the results showed that sampling size and height threshold were additional key factors that affect the estimation accuracy of biophysical parameters. Therefore, the optimal sampling size and the height threshold should be determined to improve the estimation accuracy of biophysical parameters. Our results also implied that a higher Li<span class="hlt">DAR</span> point density, larger sampling size and height threshold were required to obtain accurate corn LAI estimation when compared with height and biomass estimations. In general, our results provide valuable guidance for Li<span class="hlt">DAR</span> data acquisition and estimation of vegetation biophysical parameters using Li<span class="hlt">DAR</span> data. PMID:27410085</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010EGUGA..1214286D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010EGUGA..1214286D"><span id="translatedtitle">Towards Automation in Landcover Mapping from Li<span class="hlt">DAR</span> Data in Alpine Environment</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Dorninger, Peter; Briese, Christian; Nothegger, Clemens; Klauser, Armin</p> <p>2010-05-01</p> <p>Digital terrain models derived from airborne Li<span class="hlt">DAR</span> (often referred to as airborne laser scanning) are commonly used for various applications in geomorphology. The ongoing development in sensor technology makes flight campaigns with some 10 points per square meter economically feasible for large areas. Simultaneously, the achievable accuracy of the originally acquired points as well as those of the derived products increases due to improved measurement techniques. Additionally, full-waveform (FWF) laser scanning systems record the time-dependent strength of the backscattered signal. This allows for the determination of numerous points (i.e. echoes) for one emitted laser beam hitting multiple targets within its footprint. Practically, about five echoes may be determined from the digitized signal form. Furthermore, additional attributes can be determined for each echo. These are, for example, a reflectivity measure (amplitude), the widening of the echo (echo width), or the sequence of the echoes of a single shot. By considering the polar measurement range and atmospheric conditions, a physical calibration of such measurements is possible. The application of FWF information to increase the accuracy and the reliability of digital terrain models especially in areas with dense vegetation was shown by Doneus & Briese (2006). However, these additional attributes are rarely used for object or landcover classification. This is still the domain of automated image interpretation (e.g. Zebedin et <span class="hlt">al</span>., 2006). Nevertheless, image interpretation has well known deficiencies in areas with vegetation or if shadows occur. Therefore, we tested a hybrid approach which uses conventional first echo / last echo (FE/LE) airborne laser scanning data (first and last pulse) and an RGB-orthophoto. The testing site is located in an alpine area in Tyrol, Austria. For the classification, topographic models, a slope map, a local roughness measure and a penetration ratio were determined from the</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/23828665','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/23828665"><span id="translatedtitle">Geodetic imaging with airborne Li<span class="hlt">DAR</span>: the Earth's surface revealed.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Glennie, C L; Carter, W E; Shrestha, R L; Dietrich, W E</p> <p>2013-08-01</p> <p>The past decade has seen an explosive increase in the number of peer reviewed papers reporting new scientific findings in geomorphology (including fans, channels, floodplains and landscape evolution), geologic mapping, tectonics and faulting, coastal processes, lava flows, hydrology (especially snow and runoff routing), glaciers and geo-archaeology. A common genesis of such findings is often newly available decimeter resolution 'bare Earth' geodetic images, derived from airborne laser swath mapping, a.k.a. airborne Li<span class="hlt">DAR</span>, observations. In this paper we trace nearly a half century of advances in geodetic science made possible by space age technology, such as the invention of short-pulse-length high-pulse-rate lasers, solid state inertial measurement units, chip-based high speed electronics and the GPS satellite navigation system, that today make it possible to map hundreds of square kilometers of terrain in hours, even in areas covered with dense vegetation or shallow water. To illustrate the impact of the Li<span class="hlt">DAR</span> observations we present examples of geodetic images that are not only stunning to the eye, but help researchers to develop quantitative models explaining how terrain evolved to its present form, and how it will likely change with time. Airborne Li<span class="hlt">DAR</span> technology continues to develop quickly, promising ever more scientific discoveries in the years ahead. PMID:23828665</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013SPIE.8731E..08S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013SPIE.8731E..08S"><span id="translatedtitle">3D graph segmentation for target detection in FOPEN Li<span class="hlt">DAR</span> data</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Shorter, Nicholas; Locke, Judson; Smith, O'Neil; Keating, Emma; Smith, Philip</p> <p>2013-05-01</p> <p>A novel use of Felzenszwalb's graph based efficient image segmentation algorithm* is proposed for segmenting 3D volumetric foliage penetrating (FOPEN) Light Detection and Ranging (Li<span class="hlt">DAR</span>) data for automated target detection. The authors propose using an approximate nearest neighbors algorithm to establish neighbors of points in 3D and thus form the graph for segmentation. Following graph formation, the angular difference in the points' estimated normal vectors is proposed for the graph edge weights. Then the Li<span class="hlt">DAR</span> data is segmented, in 3D, and metrics are calculated from the segments to determine their geometrical characteristics and thus likelihood of being a target. Finally, the bare earth within the scene is automatically identified to avoid confusion of flat bare earth with flat targets. The segmentation, the calculated metrics, and the bare earth all culminate in a target detection system deployed for FOPEN Li<span class="hlt">DAR</span>. General purpose graphics processing units (GPGPUs) are leveraged to reduce processing times for the approximate nearest neighbors and point normal estimation algorithms such that the application can be run in near real time. Results are presented on several data sets.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/25207868','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/25207868"><span id="translatedtitle">Motion field estimation for a dynamic scene using a 3D Li<span class="hlt">DAR</span>.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Li, Qingquan; Zhang, Liang; Mao, Qingzhou; Zou, Qin; Zhang, Pin; Feng, Shaojun; Ochieng, Washington</p> <p>2014-01-01</p> <p>This paper proposes a novel motion field estimation method based on a 3D light detection and ranging (Li<span class="hlt">DAR</span>) sensor for motion sensing for intelligent driverless vehicles and active collision avoidance systems. Unlike multiple target tracking methods, which estimate the motion state of detected targets, such as cars and pedestrians, motion field estimation regards the whole scene as a motion field in which each little element has its own motion state. Compared to multiple target tracking, segmentation errors and data association errors have much less significance in motion field estimation, making it more accurate and robust. This paper presents an intact 3D Li<span class="hlt">DAR</span>-based motion field estimation method, including pre-processing, a theoretical framework for the motion field estimation problem and practical solutions. The 3D Li<span class="hlt">DAR</span> measurements are first projected to small-scale polar grids, and then, after data association and Kalman filtering, the motion state of every moving grid is estimated. To reduce computing time, a fast data association algorithm is proposed. Furthermore, considering the spatial correlation of motion among neighboring grids, a novel spatial-smoothing algorithm is also presented to optimize the motion field. The experimental results using several data sets captured in different cities indicate that the proposed motion field estimation is able to run in real-time and performs robustly and effectively. PMID:25207868</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2016ISPAr49B3..289L&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2016ISPAr49B3..289L&link_type=ABSTRACT"><span id="translatedtitle">An Efficient Method for Automatic Road Extraction Based on Multiple Features from Li<span class="hlt">DAR</span> Data</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Li, Y.; Hu, X.; Guan, H.; Liu, P.</p> <p>2016-06-01</p> <p>The road extraction in urban areas is difficult task due to the complicated patterns and many contextual objects. Li<span class="hlt">DAR</span> data directly provides three dimensional (3D) points with less occlusions and smaller shadows. The elevation information and surface roughness are distinguishing features to separate roads. However, Li<span class="hlt">DAR</span> data has some disadvantages are not beneficial to object extraction, such as the irregular distribution of point clouds and lack of clear edges of roads. For these problems, this paper proposes an automatic road centerlines extraction method which has three major steps: (1) road center point detection based on multiple feature spatial clustering for separating road points from ground points, (2) local principal component analysis with least squares fitting for extracting the primitives of road centerlines, and (3) hierarchical grouping for connecting primitives into complete roads network. Compared with MTH (consist of Mean shift algorithm, Tensor voting, and Hough transform) proposed in our previous article, this method greatly reduced the computational cost. To evaluate the proposed method, the Vaihingen data set, a benchmark testing data provided by ISPRS for "Urban Classification and 3D Building Reconstruction" project, was selected. The experimental results show that our method achieve the same performance by less time in road extraction using Li<span class="hlt">DAR</span> data.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013SPIE.8694E..23C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013SPIE.8694E..23C"><span id="translatedtitle">Li<span class="hlt">DAR</span> scan and smart piezo layer combined damage detection</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Chen, Shenen; Chung, Howard; Park, Youngjin</p> <p>2013-04-01</p> <p>The motivation of this study is to determine a technique to completely describe the damage state of large deformed structures commonly found during forensic investigations. The combination of Laser Detecting and Ranging (Li<span class="hlt">DAR</span>) and Piezoelectric (PZT) Sensing Technologies for damage quantification is suggested to generate the full-field description of large deformation of a plate. The test subject is a 16 inch by 16 inch aluminum plate subjected to different damage scenarios. Li<span class="hlt">DAR</span> is a static scanning laser that provides a 3-dimensional picture of the object. Smart Layer is a commercial PZT actuator/sensor network system that generates stress waves for internal damage evaluation. Both techniques were applied to the test plate after damages are introduced. In order to effectively analyze the results, the images for each test were superimposed. Frequencies that depicted the best interpretation of damage in the direct path images were superimposed with the 3-dimensional Li<span class="hlt">DAR</span> images. Four damage scenarios were imposed on an aluminum plate including saw cuts at different depths using an electric saw. The final damage is a severe bending of the plate. The bending of the specimen produced an image that located the most severe damage directly under the left hand portion and directly above the right hand portion of the bend.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015AGUFMGC13I..06H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015AGUFMGC13I..06H"><span id="translatedtitle">Supporting Indonesia's National Forest Monitoring System with Li<span class="hlt">DAR</span> Observations</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Hagen, S. C.</p> <p>2015-12-01</p> <p>Scientists at Applied GeoSolutions, Jet Propulsion Laboratory, Winrock International, and the University of New Hampshire are working with the government of Indonesia to enhance the National Forest Monitoring System in Kalimantan, Indonesia. The establishment of a reliable, transparent, and comprehensive NFMS has been limited by a dearth of relevant data that are accurate, low-cost, and spatially resolved at subnational scales. In this NASA funded project, we are developing, evaluating, and validating several critical components of a NFMS in Kalimantan, Indonesia, focusing on the use of Li<span class="hlt">DAR</span> and radar imagery for improved carbon stock and forest degradation information. Applied GeoSolutions and the University of New Hampshire have developed an Open Source Software package to process large amounts Li<span class="hlt">DAR</span> data quickly, easily, and accurately. The Open Source project is called lidar2dems and includes the classification of raw LAS point clouds and the creation of Digital Terrain Models (DTMs), Digital Surface Models (DSMs), and Canopy Height Models (CHMs). Preliminary estimates of forest structure and forest damage from logging from these data sets support the idea that comprehensive, well documented, freely available software for processing Li<span class="hlt">DAR</span> data can enable countries such as Indonesia to cost effectively monitor their forests with high precision.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015JPRS..108....1W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015JPRS..108....1W"><span id="translatedtitle">Fusion of waveform Li<span class="hlt">DAR</span> data and hyperspectral imagery for land cover classification</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Wang, Hongzhou; Glennie, Craig</p> <p>2015-10-01</p> <p>Current research into the fusion of hyperspectral imagery (HI) and full waveform Li<span class="hlt">DAR</span> (Light Detection And Ranging) has relied on first processing the full waveform Li<span class="hlt">DAR</span> (FWL) data to a set of discrete returns before merging because the data structure and sampling interval of HI and FWL are distinctly different. However, additional information about target properties can potentially be recovered if the waveform shape is preserved in the fusion process. This paper proposes a "voxelization" method to register FWL data to HI by dividing the waveform data into voxels, and then synthesizing all waveforms which intersect a voxel column into one three-dimensional superposition waveform: the synthesized waveform (SWF). A vertical energy distribution coefficients (VEDC) feature is proposed for extracting features from SWF, and then the SWF and HI are fused to form a complete feature space for classification. A pairwise classifier was adapted and completed using both Maximum Likelihood and Support Vector Machine classifiers for the combined SWF/HI features. Results show that this method of generating SWF from FWL data can effectively preserve information from the original waveforms, and the fusion of SWF and HI enhanced land cover classification compared to both using either data set alone or the merging of HI with a discrete Li<span class="hlt">DAR</span> return point cloud.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015AGUFM.H31D1436N','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015AGUFM.H31D1436N"><span id="translatedtitle">Analyzing Hydro-Geomorphic Responses in Post-Fire Stream Channels with Terrestrial Li<span class="hlt">DAR</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Nourbakhshbeidokhti, S.; Kinoshita, A. M.; Chin, A.</p> <p>2015-12-01</p> <p>Wildfires have potential to significantly alter soil properties and vegetation within watersheds. These alterations often contribute to accelerated erosion, runoff, and sediment transport in stream channels and hillslopes. This research applies repeated Terrestrial Laser Scanning (TLS) Light Detection and Ranging (Li<span class="hlt">DAR</span>) to stream reaches within the Pike National Forest in Colorado following the 2012 Waldo Canyon Fire. These scans allow investigation of the relationship between sediment delivery and environmental characteristics such as precipitation, soil burn severity, and vegetation. Post-fire Li<span class="hlt">DAR</span> images provide high resolution information of stream channel changes in eight reaches for three years (2012-2014). All images are processed with RiSCAN PRO to remove vegetation and triangulated and smoothed to create a Digital Elevation Model (DEM) with 0.1 m resolution. Study reaches with two or more successive DEM images are compared using a differencing method to estimate the volume of sediment erosion and deposition. Preliminary analysis of four channel reaches within Williams Canyon and Camp Creek yielded erosion estimates between 0.035 and 0.618 m3 per unit area. Deposition was estimated as 0.365 to 1.67 m3 per unit area. Reaches that experienced higher soil burn severity or larger rainfall events produced the greatest geomorphic changes. Results from Li<span class="hlt">DAR</span> analyses can be incorporated into post-fire hydrologic models to improve estimates of runoff and sediment yield. These models will, in turn, provide guidance for water resources management and downstream hazards mitigation.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013RPPh...76h6801G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013RPPh...76h6801G"><span id="translatedtitle">Geodetic imaging with airborne Li<span class="hlt">DAR</span>: the Earth's surface revealed</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Glennie, C. L.; Carter, W. E.; Shrestha, R. L.; Dietrich, W. E.</p> <p>2013-08-01</p> <p>The past decade has seen an explosive increase in the number of peer reviewed papers reporting new scientific findings in geomorphology (including fans, channels, floodplains and landscape evolution), geologic mapping, tectonics and faulting, coastal processes, lava flows, hydrology (especially snow and runoff routing), glaciers and geo-archaeology. A common genesis of such findings is often newly available decimeter resolution ‘bare Earth’ geodetic images, derived from airborne laser swath mapping, a.k.a. airborne Li<span class="hlt">DAR</span>, observations. In this paper we trace nearly a half century of advances in geodetic science made possible by space age technology, such as the invention of short-pulse-length high-pulse-rate lasers, solid state inertial measurement units, chip-based high speed electronics and the GPS satellite navigation system, that today make it possible to map hundreds of square kilometers of terrain in hours, even in areas covered with dense vegetation or shallow water. To illustrate the impact of the Li<span class="hlt">DAR</span> observations we present examples of geodetic images that are not only stunning to the eye, but help researchers to develop quantitative models explaining how terrain evolved to its present form, and how it will likely change with time. Airborne Li<span class="hlt">DAR</span> technology continues to develop quickly, promising ever more scientific discoveries in the years ahead.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016OptLT..77..162Y','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016OptLT..77..162Y"><span id="translatedtitle">Automatic extraction of highway light poles and towers from mobile Li<span class="hlt">DAR</span> data</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Yan, Wai Yeung; Morsy, Salem; Shaker, Ahmed; Tulloch, Mark</p> <p>2016-03-01</p> <p>Mobile Li<span class="hlt">DAR</span> has been recently demonstrated as a viable technique for pole-like object detection and classification. Despite that a desirable accuracy (around 80%) has been reported in the existing studies, majority of them were presented in the street level with relatively flat ground and very few of them addressed how to extract the entire pole structure from the ground or curb surface. Therefore, this paper attempts to fill the research gap by presenting a workflow for automatic extraction of light poles and towers from mobile Li<span class="hlt">DAR</span> data point cloud, with a particular focus on municipal highway. The data processing workflow includes (1) an automatic ground filtering mechanism to separate aboveground and ground features, (2) an unsupervised clustering algorithm to cluster the aboveground data point cloud, (3) a set of decision rules to identify and classify potential light poles and towers, and (4) a least-squares circle fitting algorithm to fit the circular pole structure so as to remove the ground points. The workflow was tested with a set of mobile Li<span class="hlt">DAR</span> data collected for a section of highway 401 located in Toronto, Ontario, Canada. The results showed that the proposed method can achieve an over 91% of detection rate for five types of light poles and towers along the study area.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010AGUFM.C33C0537S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010AGUFM.C33C0537S"><span id="translatedtitle">Estimating Basin Snow Volume Using Aerial Li<span class="hlt">DAR</span> and Binary Regression Trees (Invited)</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Shallcross, A. T.; McNamara, J. P.; Flores, A. N.; Marshall, H.; Marks, D. G.; Glenn, N. F.</p> <p>2010-12-01</p> <p>Snow cover derived from airborne Li<span class="hlt">DAR</span> (Light Detection And Ranging) is combined with binary regression trees to improve the prediction of total basin snow volume for the Dry Creek Experimental Watershed (DCEW), ID. These methods are used to identify site-specific topographic controls on the spatial distribution of snow so that future point measurements of snow depth can be distributed through space efficiently. Li<span class="hlt">DAR</span> is used to map snow cover by differencing the digital elevation models (DEMs) obtained from a snow-covered overflight and a snow-free overflight. Topographic parameters known to control snow distribution are calculated from the snow free Li<span class="hlt">DAR</span> dataset. Here, mean vegetation height, slope, aspect, solar radiation, and elevation are used to predict snow depth via a binary regression tree using ten-fold cross-validation. The branches leading to the terminal nodes of the regression tree are used to segment the watershed into homogeneous snow distribution units. Preliminary results indicate that 23 statistically significant discrete units exist. Thus, during future field campaigns, point measurements of snow depth can be gathered and distributed throughout these units. Mean measured SWE/depth of each unit can be summed to determine the total basin snow volume. This method should decrease field time and improve the accuracy of basin snow volume estimates for watershed analyses.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2016IJBm..tmp...70N&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2016IJBm..tmp...70N&link_type=ABSTRACT"><span id="translatedtitle">Assessment of human thermal perception in the hot-humid climate of <span class="hlt">Dar</span> es Salaam, Tanzania</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Ndetto, Emmanuel L.; Matzarakis, Andreas</p> <p>2016-06-01</p> <p><span class="hlt">Dar</span> es Salaam, Tanzania, is a typical African city along the Indian Ocean coast, and therefore an important urban area to examine human thermal perception in the hot-humid tropical climate. Earlier research on human bioclimate at <span class="hlt">Dar</span> es Salaam indicated that heat stress prevails during the hot season from October to March, peaking between December and February, particularly the early afternoons. In order to assess the human thermal perception and adaptation, two popular places, one at an urban park and another at a beach environment, were selected and questionnaire surveys were conducted in August-September 2013 and January 2014, concurrently with local micro-meteorological measurements at survey locations. The thermal conditions were quantified in terms of the thermal index of the physiologically equivalent temperature (PET) using the micro-scale climate model RayMan. The thermal comfort range of human thermal comfort and the local thermal adaptive capacity were determined in respect to the thermal index by binning thermal sensation votes. The thermal comfort range was found to be well above that in temperate climates at about 23-31 °C of PET. The study could significantly contribute to urban planning in <span class="hlt">Dar</span> es Salaam and other coastal cities in the tropics.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4335995','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4335995"><span id="translatedtitle"><span class="hlt">DARS</span>-associated leukoencephalopathy can mimic a steroid-responsive neuroinflammatory disorder</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Toro, Camilo; Kister, Ilya; Latif, Kartikasalwah Abd; Leventer, Richard; Pizzino, Amy; Simons, Cas; Abbink, Truus E.M.; Taft, Ryan J.; van der Knaap, Marjo S.; Vanderver, Adeline</p> <p>2015-01-01</p> <p>Objective: To describe the expanding clinical spectrum of a recently described hereditary leukoencephalopathy, hypomyelination with brainstem and spinal cord involvement and leg spasticity, which is caused by mutations in the aspartyl tRNA-synthetase encoding gene <span class="hlt">DARS</span>, including patients with an adolescent onset. Methods: Three patients with mutations in <span class="hlt">DARS</span> were identified by combining MRI pattern recognition and genetic analysis. Results: One patient had the typical infantile presentation, but 2 patients with onset in late adolescence had a disease mimicking an acquired inflammatory CNS disorder. Adolescent-onset patients presented with subacute spastic paraplegia and had positive response to steroids. They had only minor focal supratentorial white matter abnormalities, but identical spinal cord changes involving dorsal columns and corticospinal tracts. Clinical presentation included subacute spastic paraplegia with partial improvement on steroids. Conclusions: Focal T2 hyperintense white matter changes on brain MRI in combination with spinal cord signal abnormalities usually suggest acquired inflammatory conditions such as multiple sclerosis, especially in the context of relapsing course and a positive response to steroid treatment. Adolescents with mutations in <span class="hlt">DARS</span> can present with a comparable clinical picture, broadening the clinical spectrum of hypomyelination with brainstem and spinal cord involvement and leg spasticity. PMID:25527264</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015Geomo.250..236S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015Geomo.250..236S"><span id="translatedtitle">Downstream hydraulic geometry relationships: Gathering reference reach-scale width values from Li<span class="hlt">DAR</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Sofia, G.; Tarolli, P.; Cazorzi, F.; Dalla Fontana, G.</p> <p>2015-12-01</p> <p>This paper examines the ability of Li<span class="hlt">DAR</span> topography to provide reach-scale width values for the analysis of downstream hydraulic geometry relationships along some streams in the Dolomites (northern Italy). Multiple reach-scale dimensions can provide representative geometries and statistics characterising the longitudinal variability in the channel, improving the understanding of geomorphic processes across networks. Starting from the minimum curvature derived from a Li<span class="hlt">DAR</span> DTM, the proposed algorithm uses a statistical approach for the identification of the scale of analysis, and for the automatic characterisation of reach-scale bankfull widths. The downstream adjustment in channel morphology is then related to flow parameters (drainage area and stream power). With the correct planning of a Li<span class="hlt">DAR</span> survey, uncertainties in the procedure are principally due to the resolution of the DTM. The outputs are in general comparable in quality to field survey measurements, and the procedure allows the quick comparison among different watersheds. The proposed automatic approach could improve knowledge about river systems with highly variable widths, and about systems in areas covered by vegetation or inaccessible to field surveys. With proven effectiveness, this research could offer an interesting starting point for the analysis of differences between watersheds, and to improve knowledge about downstream channel adjustment in relation, for example, to scale and landscape forcing (e.g. sediment transport, tectonics, lithology, climate, geomorphology, and anthropic pressure).</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3644624','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3644624"><span id="translatedtitle">Mutations in <span class="hlt">DARS</span> Cause Hypomyelination with Brain Stem and Spinal Cord Involvement and Leg Spasticity</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Taft, Ryan J.; Vanderver, Adeline; Leventer, Richard J.; Damiani, Stephen A.; Simons, Cas; Grimmond, Sean M.; Miller, David; Schmidt, Johanna; Lockhart, Paul J.; Pope, Kate; Ru, Kelin; Crawford, Joanna; Rosser, Tena; de Coo, Irenaeus F.M.; Juneja, Monica; Verma, Ishwar C.; Prabhakar, Prab; Blaser, Susan; Raiman, Julian; Pouwels, Petra J.W.; Bevova, Marianna R.; Abbink, Truus E.M.; van der Knaap, Marjo S.; Wolf, Nicole I.</p> <p>2013-01-01</p> <p>Inherited white-matter disorders are a broad class of diseases for which treatment and classification are both challenging. Indeed, nearly half of the children presenting with a leukoencephalopathy remain without a specific diagnosis. Here, we report on the application of high-throughput genome and exome sequencing to a cohort of ten individuals with a leukoencephalopathy of unknown etiology and clinically characterized by hypomyelination with brain stem and spinal cord involvement and leg spasticity (HBSL), as well as the identification of compound-heterozygous and homozygous mutations in cytoplasmic aspartyl-tRNA synthetase (<span class="hlt">DARS</span>). These mutations cause nonsynonymous changes to seven highly conserved amino acids, five of which are unchanged between yeast and man, in the <span class="hlt">DARS</span> C-terminal lobe adjacent to, or within, the active-site pocket. Intriguingly, HBSL bears a striking resemblance to leukoencephalopathy with brain stem and spinal cord involvement and elevated lactate (LBSL), which is caused by mutations in the mitochondria-specific <span class="hlt">DARS</span>2, suggesting that these two diseases might share a common underlying molecular pathology. These findings add to the growing body of evidence that mutations in tRNA synthetases can cause a broad range of neurologic disorders. PMID:23643384</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4208193','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4208193"><span id="translatedtitle">Motion Field Estimation for a Dynamic Scene Using a 3D Li<span class="hlt">DAR</span></span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Li, Qingquan; Zhang, Liang; Mao, Qingzhou; Zou, Qin; Zhang, Pin; Feng, Shaojun; Ochieng, Washington</p> <p>2014-01-01</p> <p>This paper proposes a novel motion field estimation method based on a 3D light detection and ranging (Li<span class="hlt">DAR</span>) sensor for motion sensing for intelligent driverless vehicles and active collision avoidance systems. Unlike multiple target tracking methods, which estimate the motion state of detected targets, such as cars and pedestrians, motion field estimation regards the whole scene as a motion field in which each little element has its own motion state. Compared to multiple target tracking, segmentation errors and data association errors have much less significance in motion field estimation, making it more accurate and robust. This paper presents an intact 3D Li<span class="hlt">DAR</span>-based motion field estimation method, including pre-processing, a theoretical framework for the motion field estimation problem and practical solutions. The 3D Li<span class="hlt">DAR</span> measurements are first projected to small-scale polar grids, and then, after data association and Kalman filtering, the motion state of every moving grid is estimated. To reduce computing time, a fast data association algorithm is proposed. Furthermore, considering the spatial correlation of motion among neighboring grids, a novel spatial-smoothing algorithm is also presented to optimize the motion field. The experimental results using several data sets captured in different cities indicate that the proposed motion field estimation is able to run in real-time and performs robustly and effectively. PMID:25207868</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li class="active"><span>18</span></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_18 --> <div id="page_19" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li class="active"><span>19</span></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="361"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/25898621','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/25898621"><span id="translatedtitle">[Estimating individual tree aboveground biomass of the mid-subtropical forest using airborne Li<span class="hlt">DAR</span> technology].</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Liu, Feng; Tan, Chang; Lei, Pi-Feng</p> <p>2014-11-01</p> <p>Taking Wugang forest farm in Xuefeng Mountain as the research object, using the airborne light detection and ranging (Li<span class="hlt">DAR</span>) data under leaf-on condition and field data of concomitant plots, this paper assessed the ability of using Li<span class="hlt">DAR</span> technology to estimate aboveground biomass of the mid-subtropical forest. A semi-automated individual tree Li<span class="hlt">DAR</span> cloud point segmentation was obtained by using condition random fields and optimization methods. Spatial structure, waveform characteristics and topography were calculated as Li<span class="hlt">DAR</span> metrics from the segmented objects. Then statistical models between aboveground biomass from field data and these Li<span class="hlt">DAR</span> metrics were built. The individual tree recognition rates were 93%, 86% and 60% for coniferous, broadleaf and mixed forests, respectively. The adjusted coefficients of determination (R(2)adj) and the root mean squared errors (RMSE) for the three types of forest were 0.83, 0.81 and 0.74, and 28.22, 29.79 and 32.31 t · hm(-2), respectively. The estimation capability of model based on canopy geometric volume, tree percentile height, slope and waveform characteristics was much better than that of traditional regression model based on tree height. Therefore, Li<span class="hlt">DAR</span> metrics from individual tree could facilitate better performance in biomass estimation. PMID:25898621</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4245941','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4245941"><span id="translatedtitle">Timely binding of IHF and Fis to <span class="hlt">DARS</span>2 regulates ATP–DnaA production and replication initiation</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Kasho, Kazutoshi; Fujimitsu, Kazuyuki; Matoba, Toshihiro; Oshima, Taku; Katayama, Tsutomu</p> <p>2014-01-01</p> <p>In Escherichia coli, the ATP-bound form of DnaA (ATP–DnaA) promotes replication initiation. During replication, the bound ATP is hydrolyzed to ADP to yield the ADP-bound form (ADP–DnaA), which is inactive for initiation. The chromosomal site <span class="hlt">DARS</span>2 facilitates the regeneration of ATP–DnaA by catalyzing nucleotide exchange between free ATP and ADP bound to DnaA. However, the regulatory mechanisms governing this exchange reaction are unclear. Here, using in vitro reconstituted experiments, we show that two nucleoid-associated proteins, IHF and Fis, bind site-specifically to <span class="hlt">DARS</span>2 to activate coordinately the exchange reaction. The regenerated ATP–DnaA was fully active in replication initiation and underwent DnaA–ATP hydrolysis. ADP–DnaA formed heteromultimeric complexes with IHF and Fis on <span class="hlt">DARS</span>2, and underwent nucleotide dissociation more efficiently than ATP–DnaA. Consistently, mutant analyses demonstrated that specific binding of IHF and Fis to <span class="hlt">DARS</span>2 stimulates the formation of ATP–DnaA production, thereby promoting timely initiation. Moreover, we show that IHF–<span class="hlt">DARS</span>2 binding is temporally regulated during the cell cycle, whereas Fis only binds to <span class="hlt">DARS</span>2 in exponentially growing cells. These results elucidate the regulation of ATP–DnaA and replication initiation in coordination with the cell cycle and growth phase. PMID:25378325</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=20040059920&hterms=Stone+Age&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3D%2528Stone%2BAge%2529','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=20040059920&hterms=Stone+Age&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3D%2528Stone%2BAge%2529"><span id="translatedtitle">Rb-Sr and Sm-Nd Isotope Systematics of <span class="hlt">Shergottite</span> NWA 856: Crystallization Age and Implications for Alteration of Hot Desert SNC Meteorites</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Brandon, A. D.; Nyquist, L. E.; Shih, C.-Y.; Wiesmann, H.</p> <p>2004-01-01</p> <p>Nakhlite NWA 998 was discovered in Algeria in 2001, and is unique among the six known members of this group of Martian meteorites in containing significant modal orthopyroxene. Initial petrologic and isotopic data were reported by Irving et <span class="hlt">al</span>. This 456 gram stone consists mainly of sub-calcic augite with subordinate olivine and minor orthopyroxene, titanomagnetite, pyrrhotite, chlorapatite, and intercumulus An(sub 35) plagioclase. We report here preliminary results of radiogenic isotopic analyses conducted on fragmental material from the main mass.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2016EGUGA..1811161Q&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2016EGUGA..1811161Q&link_type=ABSTRACT"><span id="translatedtitle">Mobile Li<span class="hlt">DAR</span> Measurement for Aerosol Investigation in South-Central Hebei, China</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>qin, kai; Wu, Lixin; Zheng, Yunhui; Wong Man, Sing; Wang, Runfeng; Hu, Mingyu; Lang, Hongmei; Wang, Luyao; Bai, Yang; Rao, Lanlan</p> <p>2016-04-01</p> <p>With the rapid industrialization and urbanization in China during the last decades, the increasing anthropogenic pollutant emissions have significantly caused serious air pollution problems which are adversely influencing public health. Hebei is one of the most air polluted provinces in China. In January 2013, an extremely severe and persistent haze episode with record-breaking PM2.5 outbreak affecting hundreds of millions of people occurred over eastern and northern China. During that haze episode, 7 of the top 10 most polluted cities in China were located in the Hebei Province according to the report of China's Ministry of Environmental Protection. To investigate and the spatial difference and to characterize the vertical distribution of aerosol in different regions of south-central Hebei, mobile measurements were carried out using a mini micro pulse Li<span class="hlt">DAR</span> system (model: MiniMPL) in March 2014. The mobile Li<span class="hlt">DAR</span> kit consisting of a MiniMPL, a vibration reduction mount, a power inverter, a Windows surface tablet and a GPS receiver were mounted in a car watching though the sunroof opening. For comparison, a fixed measurement using a traditional micro pulse Li<span class="hlt">DAR</span> system (model: MPL-4B) was conducted simultaneously in Shijiazhuang, the capital of Hebei Province. The equipped car was driven from downtown Shijiazhuang by way of suburban and rural area to downtown Cangzhou, Handan, and Baoding respectively at almost stable speed around 100Km per hour along different routes which counted in total more than 1000Km. The results can be summarized as: 1) the spatial distribution of total aerosol optical depth along the measurement routes in south-central Hebei was controlled by local terrain and population in general, with high values in downtown and suburban in the plain areas, and low values in rural areas along Taihang mountain to the west and Yan mountain to the north; 2) obviously high AODs were obtained at roads crossing points, inside densely populated area and nearby</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013EGUGA..15.9073V','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013EGUGA..15.9073V"><span id="translatedtitle">Multiple-Li<span class="hlt">DAR</span> measurements of wind turbine wakes: effect of the atmospheric stability</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Valerio Iungo, Giacomo; Porté-Agel, Fernando</p> <p>2013-04-01</p> <p>Aerodynamic design and optimization of a wind farm layout are mainly based on the evaluation of wind turbine wake recovery by moving downstream, and on the characterization of wake interactions within a wind farm. Indeed, the power production of downstream wind turbine rows is strictly affected by the cumulative wake produced by the turbines deployed upstream. Wind turbine wakes are dependent on their aerodynamic features, and being immersed in the atmospheric boundary layer (ABL), they are also affected by surface heterogeneity, e.g. site topography and surface coverage, and atmospheric stability. The ABL stability is typically classified as neutral, convective or stable. In a neutral ABL the mechanical turbulent production is the dominating phenomenon. Conversely, for a convective ABL the turbulent kinetic energy and vertical transport phenomena are enhanced by positive buoyancy. Finally, for a stable ABL, a lower turbulence level is typically observed with an increased wind shear. For the present campaign convective ABL was typically observed during day-time, and neutral ABL for early morning and sunset periods. The aim of the present work is the evaluation of the influence of the ABL stability on downstream evolution of wind turbine wakes, which is mainly controlled by different ABL turbulence characteristics. Field measurements of the wake produced from a 2 MW Enercon E-70 wind turbine were performed with three scanning Doppler wind Li<span class="hlt">DARs</span>. The wind and atmospheric conditions were characterized through a sonic anemometer deployed in proximity of the wind turbine. One Li<span class="hlt">DAR</span> was placed at a distance about 12 rotor diameters upstream of the turbine in order to characterize the incoming wind. Two additional Li<span class="hlt">DARs</span> were typically used to perform wake measurements. Tests were performed over the wake vertical symmetry plane in order to characterize wake recovery. Measurements were also carried out over conical surfaces in order to investigate the wind turbine wake</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013EGUGA..1511886T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013EGUGA..1511886T"><span id="translatedtitle">Buildings classification from airborne Li<span class="hlt">DAR</span> point clouds through OBIA and ontology driven approach</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Tomljenovic, Ivan; Belgiu, Mariana; Lampoltshammer, Thomas J.</p> <p>2013-04-01</p> <p>In the last years, airborne Light Detection and Ranging (Li<span class="hlt">DAR</span>) data proved to be a valuable information resource for a vast number of applications ranging from land cover mapping to individual surface feature extraction from complex urban environments. To extract information from Li<span class="hlt">DAR</span> data, users apply prior knowledge. Unfortunately, there is no consistent initiative for structuring this knowledge into data models that can be shared and reused across different applications and domains. The absence of such models poses great challenges to data interpretation, data fusion and integration as well as information transferability. The intention of this work is to describe the design, development and deployment of an ontology-based system to classify buildings from airborne Li<span class="hlt">DAR</span> data. The novelty of this approach consists of the development of a domain ontology that specifies explicitly the knowledge used to extract features from airborne Li<span class="hlt">DAR</span> data. The overall goal of this approach is to investigate the possibility for classification of features of interest from Li<span class="hlt">DAR</span> data by means of domain ontology. The proposed workflow is applied to the building extraction process for the region of "Biberach an der Riss" in South Germany. Strip-adjusted and georeferenced airborne Li<span class="hlt">DAR</span> data is processed based on geometrical and radiometric signatures stored within the point cloud. Region-growing segmentation algorithms are applied and segmented regions are exported to the GeoJSON format. Subsequently, the data is imported into the ontology-based reasoning process used to automatically classify exported features of interest. Based on the ontology it becomes possible to define domain concepts, associated properties and relations. As a consequence, the resulting specific body of knowledge restricts possible interpretation variants. Moreover, ontologies are machinable and thus it is possible to run reasoning on top of them. Available reasoners (FACT++, JESS, Pellet) are used to check</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2005AGUFM.H31E1349C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2005AGUFM.H31E1349C"><span id="translatedtitle">A Geoinformatics Approach to Li<span class="hlt">DAR</span> / ALSM Data Distribution, Interpolation, and Analysis</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Crosby, C. J.; Conner, J.; Frank, E.; Arrowsmith, J. R.; Memon, A.; Nandigam, V.; Wurman, G.; Baru, C.</p> <p>2005-12-01</p> <p>Distribution, interpolation and analysis of large Li<span class="hlt">DAR</span> (Light Distance And Ranging, also known as ALSM (Airborne Laser Swath Mapping)) datasets pushes the computational limits of typical data distribution and processing systems. The high point-density of Li<span class="hlt">DAR</span> datasets makes grid interpolation difficult for geoscience users who lack the computing and software resources necessary to handle these massive data volumes. We are using a geoinformatics approach to the distribution, interpolation and analysis of Li<span class="hlt">DAR</span> data that capitalizes on cyberinfrastructure being developed as part of the GEON project (http://www.geongrid.org). Our approach utilizes a comprehensive workflow-based solution that begins with user-defined selection of a subset of raw data and ends with download and visualization of interpolated surfaces and derived products. The workflow environment allows us to modularize and generalize the procedure. It provides the freedom to easily plug-in new processes, to utilize existing sub workflows within an analysis, and easily extend or modify the analysis using drag-and-drop functionality through the Kepler workflow management system. In this GEON-based workflow, the billions of points within a Li<span class="hlt">DAR</span> dataset point cloud are hosted in an IBM DB2 spatial database running on the DataStar terascale computer at San Diego Supercomputer Center; a machine designed specifically for data intensive computations. Data selection is performed via an ArcIMS-based interface that allows users to execute spatial and attribute subset queries on the larger dataset. The subset of data is then passed to a GRASS Open Source GIS-based web service, "lservice", that handles interpolation to grid and analysis of the data. Lservice was developed entirely within the open source domain and offers spline and inverse distance weighted (IDW) interpolation to grid with user-defined resolution and parameters. We also compute geomorphic metrics such as slope, curvature, and aspect. Users may</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2015EGUGA..1711254F&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2015EGUGA..1711254F&link_type=ABSTRACT"><span id="translatedtitle">LESTO: an Open Source GIS-based toolbox for Li<span class="hlt">DAR</span> analysis</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Franceschi, Silvia; Antonello, Andrea; Tonon, Giustino</p> <p>2015-04-01</p> <p>During the last five years different research institutes and private companies stared to implement new algorithms to analyze and extract features from Li<span class="hlt">DAR</span> data but only a few of them also created a public available software. In the field of forestry there are different examples of software that can be used to extract the vegetation parameters from Li<span class="hlt">DAR</span> data, unfortunately most of them are closed source (even if free), which means that the source code is not shared with the public for anyone to look at or make changes to. In 2014 we started the development of the library LESTO (Li<span class="hlt">DAR</span> Empowered Sciences Toolbox Opensource): a set of modules for the analysis of Li<span class="hlt">DAR</span> point cloud with an Open Source approach with the aim of improving the performance of the extraction of the volume of biomass and other vegetation parameters on large areas for mixed forest structures. LESTO contains a set of modules for data handling and analysis implemented within the JGrassTools spatial processing library. The main subsections are dedicated to 1) preprocessing of Li<span class="hlt">DAR</span> raw data mainly in LAS format (utilities and filtering); 2) creation of raster derived products; 3) flight-lines identification and normalization of the intensity values; 4) tools for extraction of vegetation and buildings. The core of the LESTO library is the extraction of the vegetation parameters. We decided to follow the single tree based approach starting with the implementation of some of the most used algorithms in literature. These have been tweaked and applied on Li<span class="hlt">DAR</span> derived raster datasets (DTM, DSM) as well as point clouds of raw data. The methods range between the simple extraction of tops and crowns from local maxima, the region growing method, the watershed method and individual tree segmentation on point clouds. The validation procedure consists in finding the matching between field and Li<span class="hlt">DAR</span>-derived measurements at individual tree and plot level. An automatic validation procedure has been developed</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2013AGUFM.H13G1441P&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2013AGUFM.H13G1441P&link_type=ABSTRACT"><span id="translatedtitle">Seagrass Identification Using High-Resolution 532nm Bathymetric Li<span class="hlt">DAR</span> and Hyperspectral Imagery</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Pan, Z.; Prasad, S.; Starek, M. J.; Fernandez Diaz, J. C.; Glennie, C. L.; Carter, W. E.; Shrestha, R. L.; Singhania, A.; Gibeaut, J. C.</p> <p>2013-12-01</p> <p>Seagrass provides vital habitat for marine fisheries and is a key indicator species of coastal ecosystem vitality. Monitoring seagrass is therefore an important environmental initiative, but measuring details of seagrass distribution over large areas via remote sensing has proved challenging. Developments in airborne bathymetric light detection and ranging (Li<span class="hlt">DAR</span>) provide great potential in this regard. Traditional bathymetric Li<span class="hlt">DAR</span> systems have been limited in their ability to map within the shallow water zone (< 1 m) where seagrass is typically present due to limitations in receiver response and laser pulse length. Emergent short-pulse width bathymetric Li<span class="hlt">DAR</span> sensors and waveform processing algorithms enable depth measurements in shallow water environments previously inaccessible. This 3D information of the benthic layer can be applied to detect seagrass and characterize its distribution. Researchers with the National Center for Airborne Laser Mapping (NCALM) at the University of Houston (UH) and the Coastal and Marine Geospatial Sciences Lab (CMGL) of the Harte Research Institute at Texas A&M University-Corpus Christi conducted a coordinated airborne and boat-based survey of the Redfish Bay State Scientific Area as part of a collaborative study to investigate the capabilities of bathymetric Li<span class="hlt">DAR</span> and hyperspectral imaging for seagrass mapping. Redfish Bay, located along the middle Texas coast of the Gulf of Mexico, is a state scientific area designated for the purpose of protecting and studying native seagrasses. Redfish Bay is part of the broader Coastal Bend Bays estuary system recognized by the US Environmental Protection Agency (EPA) as a national estuary of significance. For this survey, UH acquired high-resolution discrete-return and full-waveform bathymetric data using their Optech Aquarius 532 nm green Li<span class="hlt">DAR</span>. In a separate flight, UH collected 2 sets of hyperspectral imaging data (1.2-m pixel resolution and 72 bands, and 0.6m pixel resolution and 36</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://pubs.er.usgs.gov/publication/70159835','USGSPUBS'); return false;" href="http://pubs.er.usgs.gov/publication/70159835"><span id="translatedtitle">Quantifying soil carbon loss and uncertainty from a peatland wildfire using multi-temporal Li<span class="hlt">DAR</span></span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Reddy, Ashwan D.; Hawbaker, Todd J.; Wurster, F.; Zhu, Zhiliang; Ward, S.; Newcomb, Doug; Murray, R.</p> <p>2015-01-01</p> <p>Peatlands are a major reservoir of global soil carbon, yet account for just 3% of global land cover. Human impacts like draining can hinder the ability of peatlands to sequester carbon and expose their soils to fire under dry conditions. Estimating soil carbon loss from peat fires can be challenging due to uncertainty about pre-fire surface elevations. This study uses multi-temporal Li<span class="hlt">DAR</span> to obtain pre- and post-fire elevations and estimate soil carbon loss caused by the 2011 Lateral West fire in the Great Dismal Swamp National Wildlife Refuge, VA, USA. We also determine how Li<span class="hlt">DAR</span> elevation error affects uncertainty in our carbon loss estimate by randomly perturbing the Li<span class="hlt">DAR</span> point elevations and recalculating elevation change and carbon loss, iterating this process 1000 times. We calculated a total loss using Li<span class="hlt">DAR</span> of 1.10 Tg C across the 25 km2 burned area. The fire burned an average of 47 cm deep, equivalent to 44 kg C/m2, a value larger than the 1997 Indonesian peat fires (29 kg C/m2). Carbon loss via the First-Order Fire Effects Model (FOFEM) was estimated to be 0.06 Tg C. Propagating the Li<span class="hlt">DAR</span> elevation error to the carbon loss estimates, we calculated a standard deviation of 0.00009 Tg C, equivalent to 0.008% of total carbon loss. We conclude that Li<span class="hlt">DAR</span> elevation error is not a significant contributor to uncertainty in soil carbon loss under severe fire conditions with substantial peat consumption. However, uncertainties may be more substantial when soil elevation loss is of a similar or smaller magnitude than the reported Li<span class="hlt">DAR</span> error.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010AGUFMOS31B1423M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010AGUFMOS31B1423M"><span id="translatedtitle">An Evaluation of Vessel Based Li<span class="hlt">DAR</span> Surveying as a Tool for Monitoring Short Term Change in Coastal Wetlands</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Mueller, C.</p> <p>2010-12-01</p> <p>Coastal wetlands are rapidly changing due to the impacts of climate change, sea-level rise, and coastal development. In light of these rapid changes, accurate and timely information on the morphology and dynamics of coastal wetlands is essential to their proper management. Currently many management agencies use aerial Li<span class="hlt">DAR</span> surveys to detect geomorphic change over large areas, allowing rapid assessment of rates of erosion and accretion. Aerial based surveys however typically can only detect vertical changes as small as 10 cm and achieve horizontal resolutions of 1 meter or more. As an alternative, vessel based Li<span class="hlt">DAR</span>, a topgraphic Li<span class="hlt">DAR</span> system mounted on a moving platform, allows for geomorphic change detection at much higher resolutions (< 1 cm horizontal and vertical for Li<span class="hlt">DAR</span>), making it possible to monitor dynamic systems over a much shorter time period and at much finer scales. The efficacy of vessel based LIDAR surveying to detect short term changes was tested in Elkhorn Slough in Monterey Bay, California using vessel based Li<span class="hlt">DAR</span> surveys completed in 2009 and 2010. These vessel-based Li<span class="hlt">DAR</span> data were merged with multibeam sonar surveys which were collected at the same time, to create complete digital elevation models of Elkhorn Slough. These data will be compared with 1998 and 2004 aerial Li<span class="hlt">DAR</span> surveys in a geographic information system for data quality, resolution, and efficacy as methods for erosion detection with results ready for presentation at the 2010 American Geophysical Union conference held in San Francisco, CA.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://pubs.er.usgs.gov/publication/70037559','USGSPUBS'); return false;" href="http://pubs.er.usgs.gov/publication/70037559"><span id="translatedtitle">Analysis of elevation changes detected from multi-temporal Li<span class="hlt">DAR</span> surveys in forested landslide terrain in western Oregon</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Burns, W.J.; Coe, J.A.; Kaya, B.S.; Ma, L.</p> <p>2010-01-01</p> <p>We examined elevation changes detected from two successive sets of Light Detection and Ranging (Li<span class="hlt">DAR</span>) data in the northern Coast Range of Oregon. The first set of Li<span class="hlt">DAR</span> data was acquired during leafon conditions and the second set during leaf-off conditions. We were able to successfully identify and map active landslides using a differential digital elevation model (DEM) created from the two Li<span class="hlt">DAR</span> data sets, but this required the use of thresholds (0.50 and 0.75 m) to remove noise from the differential elevation data, visual pattern recognition of landslideinduced elevation changes, and supplemental QuickBird satellite imagery. After mapping, we field-verified 88 percent of the landslides that we had mapped with high confidence, but we could not detect active landslides with elevation changes of less than 0.50 m. Volumetric calculations showed that a total of about 18,100 m3 of material was missing from landslide areas, probably as a result of systematic negative elevation errors in the differential DEM and as a result of removal of material by erosion and transport. We also examined the accuracies of 285 leaf-off Li<span class="hlt">DAR</span> elevations at four landslide sites using Global Positioning System and total station surveys. A comparison of Li<span class="hlt">DAR</span> and survey data indicated an overall root mean square error of 0.50 m, a maximum error of 2.21 m, and a systematic error of 0.09 m. Li<span class="hlt">DAR</span> ground-point densities were lowest in areas with young conifer forests and deciduous vegetation, which resulted in extensive interpolations of elevations in the leaf-on, bare-earth DEM. For optimal use of multi-temporal Li<span class="hlt">DAR</span> data in forested areas, we recommend that all data sets be flown during leaf-off seasons.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015PhDT........19G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015PhDT........19G"><span id="translatedtitle">Improving Li<span class="hlt">DAR</span> Data Post-Processing Techniques for Archaeological Site Management and Analysis: A Case Study from Canaveral National Seashore Park</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Griesbach, Christopher</p> <p></p> <p>Methods used to process raw Light Detection and Ranging (Li<span class="hlt">DAR</span>) data can sometimes obscure the digital signatures indicative of an archaeological site. This thesis explains the negative effects that certain Li<span class="hlt">DAR</span> data processing procedures can have on the preservation of an archaeological site. This thesis also presents methods for effectively integrating Li<span class="hlt">DAR</span> with other forms of mapping data in a Geographic Information Systems (GIS) environment in order to improve Li<span class="hlt">DAR</span> archaeological signatures by examining several pre-Columbian Native American shell middens located in Canaveral National Seashore Park (CANA).</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014AGUFM.B51C0039F','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014AGUFM.B51C0039F"><span id="translatedtitle">Estimating Mangrove Canopy Height and Above-Ground Biomass in Everglades National Park with Airbone Li<span class="hlt">DAR</span> and TanDEM-X Data.</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Feliciano, E. A.; Wdowinski, S.; Potts, M. D.; Fatoyinbo, T. E.; Lee, S. K.</p> <p>2014-12-01</p> <p>The coastal mangroves forests of Everglades National Park (ENP) are well protected from development. Nevertheless, climate change, hurricanes and other anthropogenic disturbances have affected these intertidal ecosystems. Understanding and monitoring forest structural parameters such as canopy height and above-ground biomass (AGB) are important for the establishment of an historical database for past, present and future ecosystem comparison. Forest canopy height has a well understood and directly proportional correlation with AGB. It is possible to derive it using (1) airborne Li<span class="hlt">DAR</span>/Laser Scanning (<span class="hlt">ALS</span>) or (2) space-borne radar systems such as Shuttle Radar Topography Mission (SRTM) and TanDEM-X (TDX). A previous study of the mangrove canopy height and AGB in the ENP was conducted a decade ago based on <span class="hlt">ALS</span> data acquired in 2004 in conjunction with SRTM data, which were acquired in 2000 (Simard et <span class="hlt">al</span>. 2006). In this study we estimated canopy height and AGB using an <span class="hlt">ALS</span> dataset acquired in 2012 and TDX data acquired during the years 2012-2014. The <span class="hlt">ALS</span> dataset was acquired along a 16.5 x 1.5 km swath of mangrove forest with variable canopy height. The sampled areas were representative of mangrove stature and structure in the whole ENP. Analysis of the <span class="hlt">ALS</span> dataset showed that mangrove canopy height can reach up to ~25 meters close to the coastal ENP waters. Additionally, by comparing our <span class="hlt">ALS</span> results with those of a previous study by Simard et <span class="hlt">al</span>. (2006) we identified areas where mangrove height changes greater than ± 3 meters occurred. To expand the study area to the full ENP mangrove ecosystem we processed single-polarization TDX data to obtain a Digital Canopy Model (DCM) that represents the mangrove canopy height. In order to obtain the true canopy height we calibrated the TDX phase center height with <span class="hlt">ALS</span> true canopy height. Preliminary results of a corrected single-polarized (HH) TDX scene show that mangrove canopy height can reach up to ~25 meters in the western</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015BGD....1217153S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015BGD....1217153S"><span id="translatedtitle">Structural effects of liana presence in secondary tropical dry forests using ground Li<span class="hlt">DAR</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Sánchez-Azofeifa, A.; Portillo-Quintero, C.; Durán, S. M.</p> <p>2015-10-01</p> <p>Lianas, woody vines, are a key component of tropical forest because they may reduce carbon storage potential. Lianas are increasing in density and biomass in tropical forests, but it is unknown what the potential consequences of these increases are for forest dynamics. Lianas may proliferate in disturbed areas, such as regenerating forests, but little is known about the role of lianas in secondary succession. In this study, we evaluated the potential of the ground Li<span class="hlt">DAR</span> to detect differences in the vertical structure of stands of different ages with and without lianas in tropical dry forests. Specifically, we used a terrestrial laser scanner called VEGNET to assess whether liana presence influences the vertical signature of stands of different ages, and whether successional trajectories as detected by the VEGNET could be altered by liana presence. We deployed the VEGNET ground Li<span class="hlt">DAR</span> system in 15 secondary forests of different ages early (21 years old since land abandonment), intermediate (32-35 years old) and late stages (> 80 years old) with and without lianas. We compared laser-derived vegetation components such as Plant Area Index (PAI), plant area volume density (PAVD), and the radius of gyration (RG) across forest stands between liana and no-liana treatments. In general forest stands without lianas show a clearer distinction of vertical strata and the vertical height of accumulated PAVD. A significant increase of PAI was found from intermediate to late stages in stands without lianas, but in stands where lianas were present there was not a significant trend. This suggests that lianas may be influencing successional trajectories in secondary forests, and these effects can be captured by terrestrial laser scanners such as the VEGNET. This research contributes to estimate the potential effects of lianas in secondary dry forests and highlight the role of ground Li<span class="hlt">DAR</span> to monitor structural changes in tropical forests due to liana presence.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2007AGUFM.G43D..06P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2007AGUFM.G43D..06P"><span id="translatedtitle">High-Resolution Li<span class="hlt">DAR</span> Topography of the Plate-Boundary Faults in Northern California</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Prentice, C. S.; Phillips, D. A.; Furlong, K. P.; Brown, A.; Crosby, C. J.; Bevis, M.; Shrestha, R.; Sartori, M.; Brocher, T. M.; Brown, J.</p> <p>2007-12-01</p> <p>GeoEarthScope acquired more than 1500 square km of airborne Li<span class="hlt">DAR</span> data in northern California, providing high-resolution topographic data of most of the major strike-slip faults in the region. The coverage includes the San Andreas Fault from its northern end near Shelter Cove to near Parkfield, as well as the Rodgers Creek, Maacama, Calaveras, Green Valley, Paicines, and San Gregorio Faults. The Hayward fault was added with funding provided by the US Geological Survey, the City of Berkeley, and the San Francisco Public Utilities Commission. Data coverage is typically one kilometer in width, centered on the fault. In areas of particular fault complexity the swath width was increased to two kilometers, and in selected areas swath width is as wide as five kilometers. A five-km-wide swath was flown perpendicular to the plate boundary immediately south of Cape Mendocino to capture previously unidentified faults and to understand off-fault deformation associated with the transition zone between the transform margin and the Cascadia subduction zone. The data were collected in conjunction with an intensive GPS campaign designed to improve absolute data accuracy and provide quality control. Data processing to classify the Li<span class="hlt">DAR</span> point data by return type allows users to filter out vegetation and produce high-resolution DEMs of the ground surface beneath forested regions, revealing geomorphic features along and adjacent to the faults. These data will allow more accurate mapping of fault traces in regions where the vegetation canopy has hampered this effort in the past. In addition, the data provide the opportunity to locate potential sites for detailed paleoseismic studies aimed at providing slip rates and event chronologies. The GeoEarthScope Li<span class="hlt">DAR</span> data will be made available via an interactive data distribution and processing workflow currently under development.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2016SedG..338...72S&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2016SedG..338...72S&link_type=ABSTRACT"><span id="translatedtitle">Li<span class="hlt">DAR</span>-based volume assessment of the origin of the Wadena drumlin field, Minnesota, USA</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Sookhan, Shane; Eyles, Nick; Putkinen, Niko</p> <p>2016-06-01</p> <p>The Wadena drumlin field (WDF; ~ 7500 km2) in west-central Minnesota, USA, is bordered along its outer extremity by the till-cored Alexandria moraine marking the furthest extent of the southwesterly-flowing Wadena ice lobe at c. 15,000 kyr BP. Newly available high-resolution Light Detection and Ranging (Li<span class="hlt">DAR</span>) data reveal new information regarding the number, morphology and extent of streamlined bedforms in the WDF. In addition, a newly-developed quantitative methodology based on relief curvature analysis of Li<span class="hlt">DAR</span> elevation-based raster data is used to evaluate sediment volumes represented by the WDF and its bounding end moraine. These data are used to evaluate models for the origin of drumlins. High-resolution Li<span class="hlt">DAR</span>-based mapping doubles the streamlined footprint of the Wadena Lobe to ~ 16,500 km2 increases the number of bedforms from ~ 2000 to ~ 6000, and most significantly, reclassifies large numbers of bedforms mapped previously as 'drumlins' as 'mega-scale glacial lineations' (MSGLs), indicating that the Wadena ice lobe experienced fast ice flow. The total volume of sediment in the Alexandria moraine is ~ 71-110 km3, that in the drumlins and MSGLs is ~ 2.83 km3, and the volume of swales between these bedforms is ~ 74.51 km3. The moraine volume is equivalent to a till layer 6.8 m thick across the entire bed of the Wadena lobe, suggesting drumlinization and moraine formation were accompanied by widespread lowering of the bed. This supports the hypothesis that drumlins and MSGLs are residual erosional features carved from a pre-existing till; swales represent 'missing sediment' that was eroded subglacially and advected downglacier to build the Alexandria Moraine during fast ice flow. Alternatively, the relatively small volume of sediment represented by subglacial bedforms indicates they could have formed rapidly by depositional processes.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015EGUGA..1715254H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015EGUGA..1715254H"><span id="translatedtitle">The offshore wind resources assessment application of floating Li<span class="hlt">DAR</span> in the Taiwan Strait</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Hsuan, Chung-Yao; Wu, Yu-Ting; Lin, Ta-Hui</p> <p>2015-04-01</p> <p>Wind and wave measurements of a Floating Li<span class="hlt">DAR</span> (Light Detection And Ranging) Device (FLD) are performed on the site of Fuhai Offshore Wind Farm in the Taiwan Strait. The location of the deployment is situated 10 kilometers off-coast of Changhua County, and the anchored water depth is 25 meters. It is the very first time in Asia Pacific Region to use such device for tasks of offshore wind and wave measurement. Six range gate heights were set at 55m, 71m, 90m, 110m, 150m and 200m from the FLD sensor lens. Wind speeds and wind directions were measured by a remote sensing technology. Wave heights and periods were also measured by the buoy wave sensor. A validation campaign of NCKU WindSentinel has performed by a portable Li<span class="hlt">DAR</span> (WINDCUBE v2) at Hsing-Da Harbor in the south of Taiwan from October 16th to 26th, 2013. The results showed good agreements with 10 minute averaged data of the wind speed and wind direction measured by the two Li<span class="hlt">DARs</span>. NCKU WindSentinel data are planning comparisons with Fuhai's offshore fixed mast data when the meteorological mast is completed. The goal is to convince the wind energy community that FLD are a reliable and cost effective way of obtaining data for resource assessment. Until this moment, The FLD are observing and measuring the offshore wind farm's meteorological and oceanographic data. In September of 2014, a mild typhoon (Fung-Wong) passed through from east of Taiwan. NCKU WindSentinel continuously measured during typhoon period in the sea. The present preliminary measurements campaign presented the convenient and more cost effective option of the FLD, which may be a key tool for assessment of offshore wind resources in the near-future offshore wind farm developments.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012JHyd..442...36H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012JHyd..442...36H"><span id="translatedtitle">Quantifying riparian zone structure from airborne Li<span class="hlt">DAR</span>: Vegetation filtering, anisotropic interpolation, and uncertainty propagation</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Hutton, Christopher; Brazier, Richard</p> <p>2012-06-01</p> <p>SummaryAdvances in remote sensing technology, notably in airborne Light Detection And Ranging (Li<span class="hlt">DAR</span>), have facilitated the acquisition of high-resolution topographic and vegetation datasets over increasingly large areas. Whilst such datasets may provide quantitative information on surface morphology and vegetation structure in riparian zones, existing approaches for processing raw Li<span class="hlt">DAR</span> data perform poorly in riparian channel environments. A new algorithm for separating vegetation from topography in raw Li<span class="hlt">DAR</span> data, and the performance of the Elliptical Inverse Distance Weighting (EIDW) procedure for interpolating the remaining ground points, are evaluated using data derived from a semi-arid ephemeral river. The filtering procedure, which first applies a threshold (either slope or elevation) to classify vegetation high-points, and second a regional growing algorithm from these high-points, avoids the classification of high channel banks as vegetation, preserving existing channel morphology for subsequent interpolation (2.90-9.21% calibration error; 4.53-7.44% error in evaluation for slope threshold). EIDW, which accounts for surface anisotropy by converting the remaining elevation points to streamwise co-ordinates, can outperform isoptropic interpolation (IDW) on channel banks, however, performs less well in isotropic conditions, and when local anisotropy is different to that of the main channel. A key finding of this research is that filtering parameter uncertainty affects the performance of the interpolation procedure; resultant errors may propagate into the Digital Elevation Model (DEM) and subsequently derived products, such as Canopy Height Models (CHMs). Consequently, it is important that this uncertainty is assessed. Understanding and developing methods to deal with such errors is important to inform users of the true quality of laser scanning products, such that they can be used effectively in hydrological applications.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2015SPIE.9526E..0GB&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2015SPIE.9526E..0GB&link_type=ABSTRACT"><span id="translatedtitle">Horizontal geometrical reaction time model for two-beam nacelle Li<span class="hlt">DARs</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Beuth, Thorsten; Fox, Maik; Stork, Wilhelm</p> <p>2015-06-01</p> <p>Wind energy is one of the leading sustainable energies. To attract further private and state investment in this technology, a broad scaled drop of the cost of energy has to be enforced. There is a trend towards using Laser Doppler Velocimetry Li<span class="hlt">DAR</span> systems for enhancing power output and minimizing downtimes, fatigue and extreme forces. Since most used Li<span class="hlt">DARs</span> are horizontally setup on a nacelle and work with two beams, it is important to understand the geometrical configuration which is crucial to estimate reaction times for the actuators to compensate wind gusts. In the beginning of this article, the basic operating modes of wind turbines are explained and the literature on wind behavior is analyzed to derive specific wind speed and wind angle conditions in relation to the yaw angle of the hub. A short introduction to the requirements for the reconstruction of the wind vector length and wind angle leads to the problem of wind shear detection of angled but horizontal homogeneous wind fronts due to the spatial separation of the measuring points. A distance is defined in which the wind shear of such homogeneous wind fronts is not present which is used as a base to estimate further distance calculations. The reaction time of the controller and the actuators are having a negative effect on the effective overall reaction time for wind regulation as well. In the end, exemplary calculations estimate benefits and disadvantages of system parameters for wind gust regulating Li<span class="hlt">DARs</span> for a wind turbine of typical size. An outlook shows possible future improvements concerning the vertical wind behavior.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li class="active"><span>19</span></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_19 --> <div id="page_20" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li class="active"><span>20</span></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="381"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2015PhDT.......100J&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2015PhDT.......100J&link_type=ABSTRACT"><span id="translatedtitle">Li<span class="hlt">DAR</span> Individual Tree Detection for Assessing Structurally Diverse Forest Landscapes</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Jeronimo, Sean</p> <p></p> <p>Contemporary forest management on public land incorporates a focus on restoration and maintenance of ecological functions through silvicultural manipulation of forest structure on a landscape scale. Incorporating reference conditions into restoration treatment planning and monitoring can improve treatment efficacy, but the typical ground-based methods of quantifying reference condition data---and comparing it to pre- and post-treatment stands---are expensive, time-consuming, and limited in scale. Airborne Li<span class="hlt">DAR</span> may be part of the solution to this problem, since Li<span class="hlt">DAR</span> acquisitions have both broad coverage and high resolution. I evaluated the ability of Li<span class="hlt">DAR</span> Individual Tree Detection (ITD) to describe forest structure across a structurally variable landscape in support of large-scale forest restoration. I installed nineteen 0.25 ha stem map plots across a range of structural conditions in potential reference areas (Yosemite National Park) and potential restoration treatment areas (Sierra National Forest) in the Sierra Nevada of California. I used the plots to evaluate a common ITD algorithm, the watershed transform, compare it to past uses of ITD, and determine which aspects of forest structure contributed to errors in ITD. I found that ITD across this structurally diverse landscape was generally less accurate than across the smaller and less diverse areas over which it has previously been studied. However, the pattern of tree recognition is consistent: regardless of forest structure, canopy dominants are almost always detected and relatively shorter trees are almost never detected. Correspondingly, metrics dominated by large trees, such as biomass, basal area, and spatial heterogeneity, can be measured using ITD, while metrics dominated by smaller trees, such as stand density, cannot. Bearing these limitations in mind, ITD can be a powerful tool for describing forest structure across heterogeneous landscape restoration project areas.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2016EGUGA..1816427L&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2016EGUGA..1816427L&link_type=ABSTRACT"><span id="translatedtitle">Numerical simulation of groundwater flow in <span class="hlt">Dar</span> es Salaam Coastal Plain (Tanzania)</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Luciani, Giulia; Sappa, Giuseppe; Cella, Antonella</p> <p>2016-04-01</p> <p>They are presented the results of a groundwater modeling study on the Coastal Aquifer of <span class="hlt">Dar</span> es Salaam (Tanzania). <span class="hlt">Dar</span> es Salaam is one of the fastest-growing coastal cities in Sub-Saharan Africa, with with more than 4 million of inhabitants and a population growth rate of about 8 per cent per year. The city faces periodic water shortages, due to the lack of an adequate water supply network. These two factors have determined, in the last ten years, an increasing demand of groundwater exploitation, carried on by quite a number of private wells, which have been drilled to satisfy human demand. A steady-state three dimensional groundwater model has been set up by the MODFLOW code, and calibrated with the UCODE code for inverse modeling. The aim of the model was to carry out a characterization of groundwater flow system in the <span class="hlt">Dar</span> es Salaam Coastal Plain. The inputs applied to the model included net recharge rate, calculated from time series of precipitation data (1961-2012), estimations of average groundwater extraction, and estimations of groundwater recharge, coming from zones, outside the area under study. Parametrization of the hydraulic conductivities was realized referring to the main geological features of the study area, based on available literature data and information. Boundary conditions were assigned based on hydrogeological boundaries. The conceptual model was defined in subsequent steps, which added some hydrogeological features and excluded other ones. Calibration was performed with UCODE 2014, using 76 measures of hydraulic head, taken in 2012 referred to the same season. Data were weighted on the basis of the expected errors. Sensitivity analysis of data was performed during calibration, and permitted to identify which parameters were possible to be estimated, and which data could support parameters estimation. Calibration was evaluated based on statistical index, maps of error distribution and test of independence of residuals. Further model</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2007PCE....32.1285M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2007PCE....32.1285M"><span id="translatedtitle">Residents’ perceptions of institutional performance in water supply in <span class="hlt">Dar</span> es Salaam</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Mwakalila, Shadrack</p> <p></p> <p>This paper addresses the performance of institutions in water supply systems for improving social and economic benefits of people living in <span class="hlt">Dar</span> es Salaam city. The methods employed in field data and information collection included interviews, questionnaire, focus group discussions and participatory observation. Kinondoni and Ilala Districts were used as case study. The study revealed that, the main water sources in the study areas are boreholes, shallow wells, rain water and water vendors. Other minor sources are piped water and natural water sources, such as rivers and streams. The supply of piped water by <span class="hlt">Dar</span> es Salaam Water Sewerage and Sanitation Company (DAWASA/DAWASCO) meets only 45% of the total water demands. Individuals own and sell water from boreholes, shallow wells, piped water connected to their individual houses and natural wells located in their individual plots. The price of one 20 l bucket of water from a water vendor depends on the availability of water and the distance walked from the water source to the customer. Majority of the respondents (77.5%) indicated that individual water delivery systems provide sufficient water as compared to five years ago in the study areas. Few of the respondents (6.3%) said individual water delivery systems have no capacity to provide sufficient water while 16.3% indicate that individual water delivery systems provide moderate water supply but are important in supplementing other water providers in the study areas. The study reveals that a majority of the local population are satisfied with the capacity of individual water delivery systems in providing water for household uses. This paper recommends some improvements to be done to water supply systems in the <span class="hlt">Dar</span> es Salaam city.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014SPIE.9229E..05G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014SPIE.9229E..05G"><span id="translatedtitle">Investigation on the contribution of Li<span class="hlt">DAR</span> data in 3D cadastre</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Giannaka, Olga; Dimopoulou, Efi; Georgopoulos, Andreas</p> <p>2014-08-01</p> <p>The existing 2D cadastral systems worldwide cannot provide a proper registration and representation of the land ownership rights, restrictions and responsibilities in a 3D context, which appear in our complex urban environment. Ιn such instances, it may be necessary to consider the development of a 3D Cadastre in which proprietary rights acquire appropriate three-dimensional space both above and below conventional ground level. Such a system should contain the topology and the coordinates of the buildings' outlines and infrastructure. The augmented model can be formed as a full 3D Cadastre, a hybrid Cadastre or a 2D Cadastre with 3D tags. Each country has to contemplate which alternative is appropriate, depending on the specific situation, the legal framework and the available technical means. In order to generate a 3D model for cadastral purposes, a system is required which should be able to exploit and represent 3D data such as Li<span class="hlt">DAR</span>, a remote sensing technology which acquires three-dimensional point clouds that describe the earth's surface and the objects on it. Li<span class="hlt">DAR</span> gives a direct representation of objects on the ground surface and measures their coordinates by analyzing the reflecting light. Moreover, it provides very accurate position and height information, although direct information about the objects' geometrical shape is not conveyed. In this study, an experimental implementation of 3D Cadastre using Li<span class="hlt">DAR</span> data is developed, in order to investigate if this information can satisfy the specifications that are set for the purposes of the Hellenic Cadastre. GIS tools have been used for analyzing DSM and true orthophotos of the study area. The results of this study are presented and evaluated in terms of usability and efficiency.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015AGUFMGC11B1036X','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015AGUFMGC11B1036X"><span id="translatedtitle">Quantification of uncertainty in aboveground biomass estimates derived from small-footprint Li<span class="hlt">DAR</span> data</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Xu, Q.; Greenberg, J. A.; Li, B.; Ramirez, C.; Balamuta, J. J.; Evans, K.; Man, A.; Xu, Z.</p> <p>2015-12-01</p> <p>A promising approach to determining aboveground biomass (AGB) in forests comes through the use of individual tree crown delineation (ITCD) techniques applied to small-footprint Li<span class="hlt">DAR</span> data. These techniques, when combined with allometric equations, can produce per-tree estimates of AGB. At this scale, AGB estimates can be quantified in a manner similar to how ground-based forest inventories are produced. However, these approaches have significant uncertainties that are rarely described in full. Allometric equations are often based on species-specific diameter-at-breast height (DBH) relationships, but neither DBH nor species can be reliably determined using remote sensing analysis. Furthermore, many approaches to ITCD only delineate trees appearing in the upper canopy so subcanopy trees are often missing from the inventories. In this research, we performed a propagation-of-error analysis to determine the spatially varying uncertainties in AGB estimates at the individual plant and stand level for a large collection of Li<span class="hlt">DAR</span> acquisitions covering a large portion of California. Furthermore, we determined the relative contribution of various aspects of the analysis towards the uncertainty, including errors in the ITCD results, the allometric equations, the taxonomic designation, and the local biophysical environment. Watershed segmentation was used to obtain the preliminary crown segments. Lidar points within the preliminary segments were extracted to form profiling data of the segments, and then mode detection algorithms were applied to identify the tree number and tree heights within each segment. As part of this analysis, we derived novel "remote sensing aware" allometric equations and their uncertainties based on three-dimensional morphological metrics that can be accurately derived from Li<span class="hlt">DAR</span> data.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/26072748','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/26072748"><span id="translatedtitle">Synergistic application of geometric and radiometric features of Li<span class="hlt">DAR</span> data for urban land cover mapping.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Qin, Yuchu; Li, Shihua; Vu, Tuong-Thuy; Niu, Zheng; Ban, Yifang</p> <p>2015-06-01</p> <p>Urban land cover map is essential for urban planning, environmental studies and management. This paper aims to demonstrate the potential of geometric and radiometric features derived from Li<span class="hlt">DAR</span> waveform and point cloud data in urban land cover mapping with both parametric and non-parametric classification algorithms. Small footprint Li<span class="hlt">DAR</span> waveform data acquired by RIEGL LMS-Q560 in Zhangye city, China is used in this study. A Li<span class="hlt">DAR</span> processing chain is applied to perform waveform decomposition, range determination and radiometric characterization. With the synergic utilization of geometric and radiometric features derived from Li<span class="hlt">DAR</span> data, urban land cover classification is then conducted using the Maximum Likelihood Classification (MLC), Support Vector Machines (SVM) and random forest algorithms. The results suggest that the random forest classifier achieved the most accurate result with overall classification accuracy of 91.82% and the kappa coefficient of 0.88. The overall accuracies of MLC and SVM are 84.02, and 88.48, respectively. The study suggest that the synergic utilization of geometric and radiometric features derived from Li<span class="hlt">DAR</span> data can be efficiently used for urban land cover mapping, the non-parametric random forest classifier is a promising approach for the various features with different physical meanings. PMID:26072748</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4610570','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4610570"><span id="translatedtitle">INS/GPS/Li<span class="hlt">DAR</span> Integrated Navigation System for Urban and Indoor Environments Using Hybrid Scan Matching Algorithm</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Gao, Yanbin; Liu, Shifei; Atia, Mohamed M.; Noureldin, Aboelmagd</p> <p>2015-01-01</p> <p>This paper takes advantage of the complementary characteristics of Global Positioning System (GPS) and Light Detection and Ranging (Li<span class="hlt">DAR</span>) to provide periodic corrections to Inertial Navigation System (INS) alternatively in different environmental conditions. In open sky, where GPS signals are available and Li<span class="hlt">DAR</span> measurements are sparse, GPS is integrated with INS. Meanwhile, in confined outdoor environments and indoors, where GPS is unreliable or unavailable and Li<span class="hlt">DAR</span> measurements are rich, Li<span class="hlt">DAR</span> replaces GPS to integrate with INS. This paper also proposes an innovative hybrid scan matching algorithm that combines the feature-based scan matching method and Iterative Closest Point (ICP) based scan matching method. The algorithm can work and transit between two modes depending on the number of matched line features over two scans, thus achieving efficiency and robustness concurrently. Two integration schemes of INS and Li<span class="hlt">DAR</span> with hybrid scan matching algorithm are implemented and compared. Real experiments are performed on an Unmanned Ground Vehicle (UGV) for both outdoor and indoor environments. Experimental results show that the multi-sensor integrated system can remain sub-meter navigation accuracy during the whole trajectory. PMID:26389906</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011SPIE.8174E..06A','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011SPIE.8174E..06A"><span id="translatedtitle">The use of Li<span class="hlt">DAR</span>-derived high-resolution DSM and intensity data to support modelling of urban flooding</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Aktaruzzaman, Md.; Schmitt, Theo G.</p> <p>2011-11-01</p> <p>This paper addresses the issue of a detailed representation of an urban catchment in terms of hydraulic and hydrologic attributes. Modelling of urban flooding requires a detailed knowledge of urban surface characteristics. The advancement in spatial data acquisition technology such as airborne Li<span class="hlt">DAR</span> (Light Detection and Ranging) has greatly facilitated the collection of high-resolution topographic information. While the use of the Li<span class="hlt">DAR</span>-derived Digital Surface Model (DSM) has gained popularity over the last few years as input data for a flood simulation model, the use of Li<span class="hlt">DAR</span> intensity data has remained largely unexplored in this regard. Li<span class="hlt">DAR</span> intensity data are acquired along with elevation data during the data collection mission by an aircraft. The practice of using of just aerial images with RGB (Red, Green and Blue) wavebands is often incapable of identifying types of surface under the shadow. On the other hand, Li<span class="hlt">DAR</span> intensity data can provide surface information independent of sunlight conditions. The focus of this study is the use of intensity data in combination with aerial images to accurately map pervious and impervious urban areas. This study presents an Object-Based Image Analysis (OBIA) framework for detecting urban land cover types, mainly pervious and impervious surfaces in order to improve the rainfall-runoff modelling. Finally, this study shows the application of highresolution DSM and land cover maps to flood simulation software in order to visualize the depth and extent of urban flooding phenomena.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016E%26ES...37a2010G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016E%26ES...37a2010G"><span id="translatedtitle">Unveiling topographical changes using Li<span class="hlt">DAR</span> mapping capability: case study of Belaga in Sarawak, East-Malaysia</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Ganendra, T. R.; Khan, N. M.; Razak, W. J.; Kouame, Y.; Mobarakeh, E. T.</p> <p>2016-06-01</p> <p>The use of Light Detection and Ranging (Li<span class="hlt">DAR</span>) remote sensing technology to scan and map landscapes has proven to be one of the most popular techniques to accurately map topography. Thus, Li<span class="hlt">DAR</span> technology is the ultimate method of unveiling the surface feature under dense vegetation, and, this paper intends to emphasize the diverse techniques that can be utilized to elucidate topographical changes over the study area, using multi-temporal airborne full waveform Li<span class="hlt">DAR</span> datasets collected in 2012 and 2014. Full waveform Li<span class="hlt">DAR</span> data offers access to an almost unlimited number of returns per shot, which enables the user to explore in detail topographical changes, such as vegetation growth measurement. The study also found out topography changes at the study area due to earthwork activities contributing to soil consolidation, soil erosion and runoff, requiring cautious monitoring. The implications of this study not only concurs with numerous investigations undertaken by prominent researchers to improve decision making, but also corroborates once again that investigations employing multi-temporal Li<span class="hlt">DAR</span> data to unveil topography changes in vegetated terrains, produce more detailed and accurate results than most other remote sensing data.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/26389906','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/26389906"><span id="translatedtitle">INS/GPS/Li<span class="hlt">DAR</span> Integrated Navigation System for Urban and Indoor Environments Using Hybrid Scan Matching Algorithm.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Gao, Yanbin; Liu, Shifei; Atia, Mohamed M; Noureldin, Aboelmagd</p> <p>2015-01-01</p> <p>This paper takes advantage of the complementary characteristics of Global Positioning System (GPS) and Light Detection and Ranging (Li<span class="hlt">DAR</span>) to provide periodic corrections to Inertial Navigation System (INS) alternatively in different environmental conditions. In open sky, where GPS signals are available and Li<span class="hlt">DAR</span> measurements are sparse, GPS is integrated with INS. Meanwhile, in confined outdoor environments and indoors, where GPS is unreliable or unavailable and Li<span class="hlt">DAR</span> measurements are rich, Li<span class="hlt">DAR</span> replaces GPS to integrate with INS. This paper also proposes an innovative hybrid scan matching algorithm that combines the feature-based scan matching method and Iterative Closest Point (ICP) based scan matching method. The algorithm can work and transit between two modes depending on the number of matched line features over two scans, thus achieving efficiency and robustness concurrently. Two integration schemes of INS and Li<span class="hlt">DAR</span> with hybrid scan matching algorithm are implemented and compared. Real experiments are performed on an Unmanned Ground Vehicle (UGV) for both outdoor and indoor environments. Experimental results show that the multi-sensor integrated system can remain sub-meter navigation accuracy during the whole trajectory. PMID:26389906</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015SPIE.9644E..19P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015SPIE.9644E..19P"><span id="translatedtitle">Development of the Philippine Hydrologic Dataset (PHD) from Li<span class="hlt">DAR</span> and other remotely-sensed data</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Perez, A. M. C.; Gaspa, M. C.; Aloc, D. S.; Mahor, M. A. P.; Gonzalez, K. A. C.; Borlongan, N. J. B.; De La Cruz, R. M.; Olfindo, N. T.; Blanco, A. C.</p> <p>2015-10-01</p> <p>Water resource monitoring and management has been an important concern in the Philippines, considering that the country is archipelagic in nature and is exposed to a lot of disasters imposed by the global effects of climate change. The design and implementation of an effective management scheme relies heavily on accurate, complete, and updated water resource inventories, usually in the form of digital maps and geodatabases. With the aim of developing a detailed and comprehensive database of all water resources in the Philippines, the 3-year project "Development of the Philippine Hydrologic Dataset (PHD) for Watersheds from Li<span class="hlt">DAR</span> Surveys" under the Phil-Li<span class="hlt">DAR</span> 2 Program (National Resource Inventory), has been initiated by the University of the Philippines Diliman (UPD) and the Department of Science and Technology (DOST). Various workflows has already been developed to extract inland hydrologic features in the Philippines using accurate Light Detection and Ranging (Li<span class="hlt">DAR</span>) Digital Terrain Models (DTMs) and Li<span class="hlt">DAR</span> point cloud data obtained through other government-funded programs such as Disaster Risk and Exposure Assessment for Mitigation (DREAM) and Phil-Li<span class="hlt">DAR</span> 1, supplemented with other remotely-sensed imageries and ancillary information from Local Government Units (LGUs) and National Government Agencies (NGAs). The methodologies implemented are mainly combinations of object-based image analysis, pixel-based image analysis, modeling, and field surveys. This paper presents the PHD project, the methodologies developed, and some sample outputs produced.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014OptLT..56...52G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014OptLT..56...52G"><span id="translatedtitle">The use of 1572 nm Mie Li<span class="hlt">DAR</span> for observation of the optical properties of aerosols over Wuhan, China</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Gong, Wei; Ma, Xin; Dong, Yanni; Lin, Hong; Li, Jun</p> <p>2014-03-01</p> <p>CO2 is a major component of greenhouse gases. When CO2 concentration is measured by satellites, calibration of the lower atmosphere becomes an essential procedure. Since the 1572 nm infrared region is widely used in remote sensing of CO2, we constructed a Mie Li<span class="hlt">DAR</span> system, designed to work at 1572 nm, for measuring the optical properties of aerosols in the lower troposphere. Based on the particle size distribution measured by the heliograph, the Li<span class="hlt">DAR</span> ratio is independently determined for Wuhan, China. The Li<span class="hlt">DAR</span> echo signal is then processed by the Fernald method to calculate the extinction coefficient on both clear and cloudy days. The maximum detection height is restricted by the low laser energy and quantum efficiency of the Photomultiplier Tube (PMT) used. Moreover, a simplified method for detecting the position of clouds is presented and this method is verified using a variety of passive radiation instruments that offer partial support for calibrating and verifying Li<span class="hlt">DAR</span> data. The observed results indicate that this Li<span class="hlt">DAR</span> system could be a reliable source of data support for the spaceborne remote sensing of CO2.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/24246579','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/24246579"><span id="translatedtitle">Financial sustainability in municipal solid waste management--costs and revenues in Bahir <span class="hlt">Dar</span>, Ethiopia.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Lohri, Christian Riuji; Camenzind, Ephraim Joseph; Zurbrügg, Christian</p> <p>2014-02-01</p> <p>Providing good solid waste management (SWM) services while also ensuring financial sustainability of the system continues to be a major challenge in cities of developing countries. Bahir <span class="hlt">Dar</span> in northwestern Ethiopia outsourced municipal waste services to a private waste company in 2008. While this institutional change has led to substantial improvement in the cleanliness of the city, its financial sustainability remains unclear. Is the private company able to generate sufficient revenues from their activities to offset the costs and generate some profit? This paper presents a cost-revenue analysis, based on data from July 2009 to June 2011. The analysis reveals that overall costs in Bahir <span class="hlt">Dar</span>'s SWM system increased significantly during this period, mainly due to rising costs related to waste transportation. On the other hand, there is only one major revenue stream in place: the waste collection fee from households, commercial enterprises and institutions. As the efficiency of fee collection from households is only around 50%, the total amount of revenues are not sufficient to cover the running costs. This results in a substantial yearly deficit. The results of the research therefore show that a more detailed cost structure and cost-revenue analysis of this waste management service is important with appropriate measures, either by the privates sector itself or with the support of the local authorities, in order to enhance cost efficiency and balance the cost-revenues towards cost recovery. Delays in mitigating the evident financial deficit could else endanger the public-private partnership (PPP) and lead to failure of this setup in the medium to long term, thus also endangering the now existing improved and currently reliable service. We present four options on how financial sustainability of the SWM system in Bahir <span class="hlt">Dar</span> might be enhanced: (i) improved fee collection efficiency by linking the fees of solid waste collection to water supply; (ii) increasing the value</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013ISPAn.II5b..61C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013ISPAn.II5b..61C"><span id="translatedtitle">Temporal Analysis and Automatic Calibration of the Velodyne HDL-32E Li<span class="hlt">DAR</span> System</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Chan, T. O.; Lichti, D. D.; Belton, D.</p> <p>2013-10-01</p> <p>At the end of the first quarter of 2012, more than 600 Velodyne Li<span class="hlt">DAR</span> systems had been sold worldwide for various robotic and high-accuracy survey applications. The ultra-compact Velodyne HDL-32E Li<span class="hlt">DAR</span> has become a predominant sensor for many applications that require lower sensor size/weight and cost. For high accuracy applications, cost-effective calibration methods with minimal manual intervention are always desired by users. However, the calibrations are complicated by the Velodyne Li<span class="hlt">DAR</span>'s narrow vertical field of view and the very highly time-variant nature of its measurements. In the paper, the temporal stability of the HDL-32E is first analysed as the motivation for developing a new, automated calibration method. This is followed by a detailed description of the calibration method that is driven by a novel segmentation method for extracting vertical cylindrical features from the Velodyne point clouds. The proposed segmentation method utilizes the Velodyne point cloud's slice-like nature and first decomposes the point clouds into 2D layers. Then the layers are treated as 2D images and are processed with the Generalized Hough Transform which extracts the points distributed in circular patterns from the point cloud layers. Subsequently, the vertical cylindrical features can be readily extracted from the whole point clouds based on the previously extracted points. The points are passed to the calibration that estimates the cylinder parameters and the Li<span class="hlt">DAR</span>'s additional parameters simultaneously by constraining the segmented points to fit to the cylindrical geometric model in such a way the weighted sum of the adjustment residuals are minimized. The proposed calibration is highly automatic and this allows end users to obtain the time-variant additional parameters instantly and frequently whenever there are vertical cylindrical features presenting in scenes. The methods were verified with two different real datasets, and the results suggest that up to 78</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/27322279','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/27322279"><span id="translatedtitle">Scan Line Based Road Marking Extraction from Mobile Li<span class="hlt">DAR</span> Point Clouds.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Yan, Li; Liu, Hua; Tan, Junxiang; Li, Zan; Xie, Hong; Chen, Changjun</p> <p>2016-01-01</p> <p>Mobile Mapping Technology (MMT) is one of the most important 3D spatial data acquisition technologies. The state-of-the-art mobile mapping systems, equipped with laser scanners and named Mobile Li<span class="hlt">DAR</span> Scanning (MLS) systems, have been widely used in a variety of areas, especially in road mapping and road inventory. With the commercialization of Advanced Driving Assistance Systems (ADASs) and self-driving technology, there will be a great demand for lane-level detailed 3D maps, and MLS is the most promising technology to generate such lane-level detailed 3D maps. Road markings and road edges are necessary information in creating such lane-level detailed 3D maps. This paper proposes a scan line based method to extract road markings from mobile Li<span class="hlt">DAR</span> point clouds in three steps: (1) preprocessing; (2) road points extraction; (3) road markings extraction and refinement. In preprocessing step, the isolated Li<span class="hlt">DAR</span> points in the air are removed from the Li<span class="hlt">DAR</span> point clouds and the point clouds are organized into scan lines. In the road points extraction step, seed road points are first extracted by Height Difference (HD) between trajectory data and road surface, then full road points are extracted from the point clouds by moving least squares line fitting. In the road markings extraction and refinement step, the intensity values of road points in a scan line are first smoothed by a dynamic window median filter to suppress intensity noises, then road markings are extracted by Edge Detection and Edge Constraint (EDEC) method, and the Fake Road Marking Points (FRMPs) are eliminated from the detected road markings by segment and dimensionality feature-based refinement. The performance of the proposed method is evaluated by three data samples and the experiment results indicate that road points are well extracted from MLS data and road markings are well extracted from road points by the applied method. A quantitative study shows that the proposed method achieves an average</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014EGUGA..16.9678F','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014EGUGA..16.9678F"><span id="translatedtitle">Landslide displacement vectors derived from multi-temporal topographic Li<span class="hlt">DAR</span> data</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Fey, Christine; Rutzinger, Martin; Bremer, Magnus; Prager, Christoph; Zangerl, Christian</p> <p>2014-05-01</p> <p>Information about slope geometry and kinematics of landslides is essential for hazard assessment, monitoring and planning of protection and mitigation measures. Especially for remote and inaccessible slopes, subsurface data (e.g. boreholes, tunnels, investigation adits) are often not available and thus the deformation characteristics must be derived from surface displacement data. In recent years, multi-temporal topographic Li<span class="hlt">DAR</span> (Light Detection and Ranging) data became an increasingly improved tool for detecting topographic surface deformations. In this context, Li<span class="hlt">DAR</span>-based change detection is commonly applied for quantifying surface elevation changes. Advanced change detection methods derive displacement vectors with direction and velocities of slope movements. To extract displacement vectors from Li<span class="hlt">DAR</span> raster data (i) an approach based on feature tracking by image correlation and (ii) an approach based on feature tracking by vectors breaklines are investigated. The image correlation method is based on the IMCORR software (National Snow and Ice Data Center, University of Colorado, Boulder), implemented in a SAGA GIS module. The image correlation algorithm is based on a normalized cross-covariance method. The algorithm searches tie points in two feature rasters derived from a digital surface model acquired at different time stamps. The method assesses automatically the displacement rates and directions of distinct terrain features e.g. displaced mountain ridges or striking boulders. In contrast the vector-based breakline methods require manual selection of tie points. The breaklines are the product of vectorized curvature raster images and extracting the "upper terrain edges" (topographic ridges) and "lower terrain edges" (topographic depressions). Both methods were tested on simulated terrain with determined displacement rates in order to quantify i) the accuracy ii) the minimum detectable movement rates iii) the influence of terrain characteristics iv) the</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010AGUFM.H42B..03K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010AGUFM.H42B..03K"><span id="translatedtitle">Processing and evaluation of riverine waveforms acquired by an experimental bathymetric Li<span class="hlt">DAR</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kinzel, P. J.; Legleiter, C. J.; Nelson, J. M.</p> <p>2010-12-01</p> <p>Accurate mapping of fluvial environments with airborne bathymetric Li<span class="hlt">DAR</span> is challenged not only by environmental characteristics but also the development and application of software routines to post-process the recorded laser waveforms. During a bathymetric Li<span class="hlt">DAR</span> survey, the transmission of the green-wavelength laser pulses through the water column is influenced by a number of factors including turbidity, the presence of organic material, and the reflectivity of the streambed. For backscattered laser pulses returned from the river bottom and digitized by the Li<span class="hlt">DAR</span> detector, post-processing software is needed to interpret and identify distinct inflections in the reflected waveform. Relevant features of this energy signal include the air-water interface, volume reflection from the water column itself, and, ideally, a strong return from the bottom. We discuss our efforts to acquire, analyze, and interpret riverine surveys using the USGS Experimental Advanced Airborne Research Li<span class="hlt">DAR</span> (EAARL) in a variety of fluvial environments. Initial processing of data collected in the Trinity River, California, using the EAARL Airborne Lidar Processing Software (ALPS) highlighted the difficulty of retrieving a distinct bottom signal in deep pools. Examination of laser waveforms from these pools indicated that weak bottom reflections were often neglected by a trailing edge algorithm used by ALPS to process shallow riverine waveforms. For the Trinity waveforms, this algorithm had a tendency to identify earlier inflections as the bottom, resulting in a shallow bias. Similarly, an EAARL survey along the upper Colorado River, Colorado, also revealed the inadequacy of the trailing edge algorithm for detecting weak bottom reflections. We developed an alternative waveform processing routine by exporting digitized laser waveforms from ALPS, computing the local extrema, and fitting Gaussian curves to the convolved backscatter. Our field data indicate that these techniques improved the</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4934329','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4934329"><span id="translatedtitle">Scan Line Based Road Marking Extraction from Mobile Li<span class="hlt">DAR</span> Point Clouds†</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Yan, Li; Liu, Hua; Tan, Junxiang; Li, Zan; Xie, Hong; Chen, Changjun</p> <p>2016-01-01</p> <p>Mobile Mapping Technology (MMT) is one of the most important 3D spatial data acquisition technologies. The state-of-the-art mobile mapping systems, equipped with laser scanners and named Mobile Li<span class="hlt">DAR</span> Scanning (MLS) systems, have been widely used in a variety of areas, especially in road mapping and road inventory. With the commercialization of Advanced Driving Assistance Systems (ADASs) and self-driving technology, there will be a great demand for lane-level detailed 3D maps, and MLS is the most promising technology to generate such lane-level detailed 3D maps. Road markings and road edges are necessary information in creating such lane-level detailed 3D maps. This paper proposes a scan line based method to extract road markings from mobile Li<span class="hlt">DAR</span> point clouds in three steps: (1) preprocessing; (2) road points extraction; (3) road markings extraction and refinement. In preprocessing step, the isolated Li<span class="hlt">DAR</span> points in the air are removed from the Li<span class="hlt">DAR</span> point clouds and the point clouds are organized into scan lines. In the road points extraction step, seed road points are first extracted by Height Difference (HD) between trajectory data and road surface, then full road points are extracted from the point clouds by moving least squares line fitting. In the road markings extraction and refinement step, the intensity values of road points in a scan line are first smoothed by a dynamic window median filter to suppress intensity noises, then road markings are extracted by Edge Detection and Edge Constraint (EDEC) method, and the Fake Road Marking Points (FRMPs) are eliminated from the detected road markings by segment and dimensionality feature-based refinement. The performance of the proposed method is evaluated by three data samples and the experiment results indicate that road points are well extracted from MLS data and road markings are well extracted from road points by the applied method. A quantitative study shows that the proposed method achieves an average</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2009AGUFMED51A0519R&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2009AGUFMED51A0519R&link_type=ABSTRACT"><span id="translatedtitle">Wallace Creek Virtual Field Trip: Teaching Geoscience Concepts with Li<span class="hlt">DAR</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Robinson, S. E.; Arrowsmith, R.; Crosby, C. J.</p> <p>2009-12-01</p> <p>Recently available data such as Li<span class="hlt">DAR</span> (Light Detection and Ranging) high-resolution topography can assist students to better visualize and understand geosciences concepts. It is important to bring these data into geosciences curricula as teaching aids while ensuring that the visualization tools, virtual environments, etc. do not serve as barriers to student learning. As a Southern California Earthquake Center ACCESS-G intern, I am creating a “virtual field trip” to Wallace Creek along the San Andreas Fault (SAF) using Google Earth as a platform and the B4 project Li<span class="hlt">DAR</span> data. Wallace Creek is an excellent site for understanding the centennial-to-millennial record of SAF slip because of its dramatic stream offsets. Using the Li<span class="hlt">DAR</span> data instead of, or alongside, traditional visualizations and teaching methods enhances a student’s ability to understand plate tectonics, the earthquake cycle, strike-slip faults, and geomorphology. Viewing a high-resolution representation of the topography in Google Earth allows students to analyze the landscape and answer questions about the behavior of the San Andreas Fault. The activity guides students along the fault allowing them to measure channel offsets using the Google Earth measuring tool. Knowing the ages of channels, they calculate slip rate. They look for the smallest channel offsets around Wallace Creek in order to determine the slip per event. At both a “Li<span class="hlt">DAR</span> and Education” workshop and the Cyberinfrastructure Summer Institute for Geoscientists (CSIG), I presented the Wallace Creek activity to high school and college earth science teachers. The teachers were positive in their responses and had numerous important suggestions including the need for a teacher’s manual for instruction and scientific background, and that the student goals and science topics should be specific and well-articulated for the sake of both the teacher and the student. The teachers also noted that the technology in classrooms varies</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2009PhDT.......342S&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2009PhDT.......342S&link_type=ABSTRACT"><span id="translatedtitle">Unsupervised building detection from irregularly spaced Li<span class="hlt">DAR</span> and aerial imagery</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Shorter, Nicholas Sven</p> <p></p> <p>As more data sources containing 3-D information are becoming available, an increased interest in 3-D imaging has emerged. Among these is the 3-D reconstruction of buildings and other man-made structures. A necessary preprocessing step is the detection and isolation of individual buildings that subsequently can be reconstructed in 3-D using various methodologies. Applications for both building detection and reconstruction have commercial use for urban planning, network planning for mobile communication (cell phone tower placement), spatial analysis of air pollution and noise nuisances, microclimate investigations, geographical information systems, security services and change detection from areas affected by natural disasters. Building detection and reconstruction are also used in the military for automatic target recognition and in entertainment for virtual tourism. Previously proposed building detection and reconstruction algorithms solely utilized aerial imagery. With the advent of Light Detection and Ranging (Li<span class="hlt">DAR</span>) systems providing elevation data, current algorithms explore using captured Li<span class="hlt">DAR</span> data as an additional feasible source of information. Additional sources of information can lead to automating techniques (alleviating their need for manual user intervention) as well as increasing their capabilities and accuracy. Several building detection approaches surveyed in the open literature have fundamental weaknesses that hinder their use; such as requiring multiple data sets from different sensors, mandating certain operations to be carried out manually, and limited functionality to only being able to detect certain types of buildings. In this work, a building detection system is proposed and implemented which strives to overcome the limitations seen in existing techniques. The developed framework is flexible in that it can perform building detection from just Li<span class="hlt">DAR</span> data (first or last return), or just nadir, color aerial imagery. If data from both Li<span class="hlt">DAR</span> and</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li class="active"><span>20</span></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_20 --> <div id="page_21" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li class="active"><span>21</span></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="401"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012EGUGA..14..442K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012EGUGA..14..442K"><span id="translatedtitle">Using High-Resolution Airborne Li<span class="hlt">DAR</span>-Data for Landslide Mapping in the Eastern Alps</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kamp, N.</p> <p>2012-04-01</p> <p>Due to the increasing frequency of natural disasters like floods and landslides, the active remote sensing technique Li<span class="hlt">DAR</span> (Light Detection and Ranging), has become a topic of great interest to the Federal State Government of Styria, Federal Republic of Austria. In a perennial project from 2008 to 2012 high-resolution 3D Airborne Li<span class="hlt">DAR</span> Data of the Province of Styria, an area about 16.000km2 in south-eastern Austria were collected. These data were processed to create Digital Terrain Models (DTM) and Digital Surface Models (DSM) at 1m resolution with a vertical accuracy of 15 [cm] and a positional accuracy of 40 [cm]. High resolution DTMs can be used in different geo-related applications like geomorphological mapping or natural hazard mapping. DTMs show because of its high accuracy various natural and anthropogenic terrain features such as erosion scarps, alluvial fans, landslides, old creeks, topographic edges and karstforms, as well as walking paths and roads and in addition to that Li<span class="hlt">DAR</span> data allows the detection and outlining of these different geomorphological and anthropogenic features with the help of ArcGIS 10 geoprocessing and analysing techniques, mathematical, statistical and image processing methods and the open source scripting language Python. As a result complex workflows and new geoprocessing tools can be implemented in an ArcGIS 10 workspace and are provided as easy to use toolbox contents. The landslide phenomena take in centre stage of the research work of the author. Thereby the main focus is targeted on sliding movements out of soils and bedrock. Factors like gravity take effect on slope stability directly and cause complex mass movements with a downslope directed, gliding movement of bed- and/or loose-rock as well as soil material. In this paper the author presents the result of her master thesis, an automatic ArcGIS 10 landslide mapping tool using high-resolution Li<span class="hlt">DAR</span> data in the rock masses of the Eastern Alps (Province of Styria, Austria</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2014JMEP...23.1815C&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2014JMEP...23.1815C&link_type=ABSTRACT"><span id="translatedtitle"><span class="hlt">Al</span> Composites</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Chandanayaka, Tharaka; Azarmi, Fardad</p> <p>2014-05-01</p> <p>In the present study, cold spraying technique was used to fabricate a metal matrix composite (MMC) that consists of Ni matrix and 20 vol.% Ni3<span class="hlt">Al</span> particles at two different particle sizes as reinforcement. This study intends to investigate the effect of reinforcement particle size on microstructural and mechanical properties of cold sprayed MMCs. Two different Ni3<span class="hlt">Al</span> powders with nominal particle size of -45 to +5 and +45 to 100 μm were used as reinforcement in this study. Cold sprayed Ni-Ni3<span class="hlt">Al</span> samples were subjected to the microstructural observation and characterization prior to any mechanical testing. Then, samples were tested using nano-indentation, Knoop hardness, Vickers hardness, and Resonance frequency to evaluate their mechanical properties. No significant changes were observed in microstructural characteristics due to different particle sizes. The results obtained from a variety of mechanical testings indicated that the increasing reinforcement particle size resulted in the slight reduction of mechanical properties such as elastic modulus and hardness in cold sprayed MMCs. The mechanical interlock between deposited particles defines the bonding strength in cold sprayed samples. Small size particles have a higher velocity and impact resulting in stronger interlock between deformed particles.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013SPIE.8870E..09I','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013SPIE.8870E..09I"><span id="translatedtitle">Using a new GUI tool to leverage Li<span class="hlt">DAR</span> data to aid in hyperspectral image material detection in the radiance domain on RIT SHARE Li<span class="hlt">DAR</span>/HSI data</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Ientilucci, Emmett J.</p> <p>2013-09-01</p> <p>This paper looks at a data set, called the SHARE 2010 collect, that has been designed to analyze the various impacts of illumination change on materials. Similar fabric materials were placed on different backgrounds where spectral signatures were analyzed to determined impacts of background adjacency. Hyperspectral, multispectral, and Li<span class="hlt">DAR</span> modalities were used to image the panels in the above mentioned scenarios. Applications such as material detection with results are used to assess difficulties with finding such panels. The incorporation of point Li<span class="hlt">DAR</span> data sets and physical models will aid in approximating the correct per-pixel signature to be used in the above mentioned detection scheme. This technique can help mitigate issues related to varying illumination across a scene. All of the processing (i.e., Li<span class="hlt">DAR</span>, MODTRAN, HSI and detection) is performed in a new GUI tool which runs in the ENVI software.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3495844','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3495844"><span id="translatedtitle"><span class="hlt">AL</span> Amyloidosis</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p></p> <p>2012-01-01</p> <p>Definition of the disease <span class="hlt">AL</span> amyloidosis results from extra-cellular deposition of fibril-forming monoclonal immunoglobulin (Ig) light chains (LC) (most commonly of lambda isotype) usually secreted by a small plasma cell clone. Most patients have evidence of isolated monoclonal gammopathy or smoldering myeloma, and the occurrence of <span class="hlt">AL</span> amyloidosis in patients with symptomatic multiple myeloma or other B-cell lymphoproliferative disorders is unusual. The key event in the development of <span class="hlt">AL</span> amyloidosis is the change in the secondary or tertiary structure of an abnormal monoclonal LC, which results in instable conformation. This conformational change is responsible for abnormal folding of the LC, rich in β leaves, which assemble into monomers that stack together to form amyloid fibrils. Epidemiology <span class="hlt">AL</span> amyloidosis is the most common type of systemic amyloidois in developed countries with an estimated incidence of 9 cases/million inhabitant/year. The average age of diagnosed patients is 65 years and less than 10% of patients are under 50. Clinical description The clinical presentation is protean, because of the wide number of tissues or organs that may be affected. The most common presenting symptoms are asthenia and dyspnoea, which are poorly specific and may account for delayed diagnosis. Renal manifestations are the most frequent, affecting two thirds of patients at presentation. They are characterized by heavy proteinuria, with nephrotic syndrome and impaired renal function in half of the patients. Heart involvement, which is present at diagnosis in more than 50% of patients, leading to restrictive cardiopathy, is the most serious complication and engages prognosis. Diagnostic methods The diagnosis relies on pathological examination of an involved site showing Congo red-positive amyloid deposits, with typical apple-green birefringence under polarized light, that stain positive with an anti-LC antibody by immunohistochemistry and/or immunofluorescence. Due to the</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015EGUGA..1712529K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015EGUGA..1712529K"><span id="translatedtitle">Airborne Li<span class="hlt">DAR</span> data as a key element of the integrated monitoring of the reservoir shore zone development</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kaczmarek, Halina</p> <p>2015-04-01</p> <p>The research of the transformation of the shore zone of artificial water reservoirs are long-term monitoring studies, often covering the entire length of the shoreline of the tested basin. Extremely valuable sources of data in such studies are variously dated cartographic materials: large-scale maps and surveying plans as well as aerial photographs. In recent years, the materials derived from the airborne laser scanning, i.e. light detection and ranging (Li<span class="hlt">DAR</span>) which are among the most accurate terrain data, gained importance. The possibility of using data from the airborne laser scanning in the studies of the transformation of the shore zone of a water reservoir will be presented on the example of the Jeziorsko Reservoir on the Warta River (Central Poland). The reservoir was created in the years 1986-1992. It is a typical retention reservoir with large, nearly 5-m, water level changes in a yearly cycle. Its total surface area, depending on the water level, is between 19.6 km2 and 242.3 km2. The total length of the shore is 44.3 km, of which 14.2 km (32.1%) are embanked. Nearly 40% of the non-embanked shore is still active, and its development is the result of the processes of shoreline erosion, mass movements and accumulation. Most problems are caused by the abrasive shores which represent 27% of the non-embanked shoreline. The height of the accompanying cliff varies from a few cm to 12.5 m. In the years 1991-2009 the shoreline of the reservoir retreated by 6.9 to 18.7 m in the northern part of the reservoir (the cliff of 1-12.2 m) and by 9 to 29.6 m in its southern part (the cliff of 2.0-8.5 m). The cliff recession pace with the development of the shore zone significantly decreased; in the northern part of the reservoir the cliff recession dropped from 1.5 m/y in 1991-2004 to 0.5 m/y in 2004-2009, while in the southern part - from 0.7-2.22 m/y in 1991-2004 to 0-1.12 m/y in 2004-2009. The study used the airborne Li<span class="hlt">DAR</span> data from the years 2009 and 2011 in the <span class="hlt">ALS</span></p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://pubs.er.usgs.gov/publication/70032310','USGSPUBS'); return false;" href="http://pubs.er.usgs.gov/publication/70032310"><span id="translatedtitle">The use of local indicators of spatial association to improve Li<span class="hlt">DAR</span>-derived predictions of potential amphibian breeding ponds</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Julian, J.T.; Young, J.A.; Jones, J.W.; Snyder, C.D.; Wright, C.W.</p> <p>2009-01-01</p> <p>We examined whether spatially explicit information improved models that use Li<span class="hlt">DAR</span> return signal intensity to discriminate in-pond habitat from terrestrial habitat at 24 amphibian breeding ponds. The addition of Local Indicators of Spatial Association (LISA) to Li<span class="hlt">DAR</span> return intensity data significantly improved predictive models at all ponds, reduced residual error by as much as 74%, and appeared to improve models by reducing classification errors associated with types of in-pond vegetation. We conclude that LISA statistics can help maximize the information content that can be extracted from time resolved Li<span class="hlt">DAR</span> return data in models that predict the occurrence of small, seasonal ponds. ?? Springer-Verlag 2008.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4761793','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4761793"><span id="translatedtitle">Characterizing Croatian Wheat Germplasm Diversity and Structure in a European Context by <span class="hlt">DAr</span>T Markers</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Novoselović, Dario; Bentley, Alison R.; Šimek, Ruđer; Dvojković, Krešimir; Sorrells, Mark E.; Gosman, Nicolas; Horsnell, Richard; Drezner, Georg; Šatović, Zlatko</p> <p>2016-01-01</p> <p>Narrowing the genetic base available for future genetic progress is a major concern to plant breeders. In order to avoid this, strategies to characterize and protect genetic diversity in regional breeding pools are required. In this study, 89 winter wheat cultivars released in Croatia between 1936 and 2006 were genotyped using 1,229 <span class="hlt">DAr</span>T (diversity array technology) markers to assess the diversity and population structure. In order to place Croatian breeding pool (CBP) in a European context, Croatian wheat cultivars were compared to 523 European cultivars from seven countries using a total of 166 common <span class="hlt">DAr</span>T markers. The results show higher genetic diversity in the wheat breeding pool from Central Europe (CE) as compared to that from Northern and Western European (NWE) countries. The most of the genetic diversity was attributable to the differences among cultivars within countries. When the geographical criterion (CE vs. NWE) was applied, highly significant difference between regions was obtained that accounted for 16.19% of the total variance, revealing that the CBP represents genetic variation not currently captured in elite European wheat. The current study emphasizes the important contribution made by plant breeders to maintaining wheat genetic diversity and suggests that regional breeding is essential to the maintenance of this diversity. The usefulness of open-access wheat datasets is also highlighted. PMID:26941756</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4999160','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4999160"><span id="translatedtitle">Identifying Ancient Settlement Patterns through Li<span class="hlt">DAR</span> in the Mosquitia Region of Honduras</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Fernández-Diaz, Juan Carlos; Cohen, Anna S.; Neil Cruz, Oscar; Gonzáles, Alicia M.; Leisz, Stephen J.; Pezzutti, Florencia; Shrestha, Ramesh; Carter, William</p> <p>2016-01-01</p> <p>The Mosquitia ecosystem of Honduras occupies the fulcrum between the American continents and as such constitutes a critical region for understanding past patterns of socio-political development and interaction. Heavy vegetation, rugged topography, and remoteness have limited scientific investigation. This paper presents prehistoric patterns of settlement and landuse for a critical valley within the Mosquitia derived from airborne Li<span class="hlt">DAR</span> scanning and field investigation. We show that (i) though today the valley is a wilderness it was densely inhabited in the past; (ii) that this population was organized into a three-tiered system composed of 19 settlements dominated by a city; and, (iii) that this occupation was embedded within a human engineered landscape. We also add to a growing body of literature that demonstrates the utility of Li<span class="hlt">DAR</span> as means for rapid cultural assessments in undocumented regions for analysis and conservation. Our ultimate hope is for our work to promote protections to safeguard the unique and critically endangered Mosquitia ecosystem and other similar areas in need of preservation. PMID:27560962</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015JPRS..101...22W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015JPRS..101...22W"><span id="translatedtitle">A comparison of waveform processing algorithms for single-wavelength Li<span class="hlt">DAR</span> bathymetry</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Wang, Chisheng; Li, Qingquan; Liu, Yanxiong; Wu, Guofeng; Liu, Peng; Ding, Xiaoli</p> <p>2015-03-01</p> <p>Due to the low-cost and lightweight units, single-wavelength Li<span class="hlt">DAR</span> bathymetric systems are an ideal option for shallow-water (<12 m) bathymetry. However, one disadvantage of such systems is the lack of near-infrared and Raman channels, which results in difficulties in extracting the water surface. Therefore, the choice of a suitable waveform processing method is extremely important to guarantee the accuracy of the bathymetric retrieval. In this paper, we test six algorithms for single-wavelength bathymetric waveform processing, i.e. peak detection (PD), the average square difference function (ASDF), Gaussian decomposition (GD), quadrilateral fitting (QF), Richardson-Lucy deconvolution (RLD), and Wiener filter deconvolution (WD). To date, most of these algorithms have previously only been applied in topographic Li<span class="hlt">DAR</span> waveforms captured over land. A simulated dataset and an Optech Aquarius dataset were used to assess the algorithms, with the focus being on their capability of extracting the depth and the bottom response. The influences of a number of water and equipment parameters were also investigated by the use of a Monte Carlo method. The results showed that the RLD method had a superior performance in terms of a high detection rate and low errors in the retrieved depth and magnitude. The attenuation coefficient, noise level, water depth, and bottom reflectance had significant influences on the measurement error of the retrieved depth, while the effects of scan angle and water surface roughness were not so obvious.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015WRR....5110029H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015WRR....5110029H"><span id="translatedtitle">Wet channel network extraction by integrating Li<span class="hlt">DAR</span> intensity and elevation data</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Hooshyar, Milad; Kim, Seoyoung; Wang, Dingbao; Medeiros, Stephen C.</p> <p>2015-12-01</p> <p>The temporal dynamics of stream networks are vitally important for understanding hydrologic processes including surface water and groundwater interaction and hydrograph recession. However, observations of wet channel networks are limited, especially in headwater catchments. Near-infrared Li<span class="hlt">DAR</span> data provide an opportunity to map wet channel networks owing to the fine spatial resolution and strong absorption of light energy by water surfaces. A systematic method is developed to map wet channel networks by integrating elevation and signal intensity of ground returns. The signal intensity thresholds for identifying wet pixels are extracted from frequency distributions of intensity return within the convergent topography extent using a Gaussian mixture model. Moreover, the concept of edge in digital image processing, defined based on the intensity gradient, is utilized to enhance detection of small wet channels. The developed method is applied to the Lake Tahoe area based on eight Li<span class="hlt">DAR</span> snapshots during recession periods in five watersheds. A power law relationship between streamflow and wetted channel length during recession periods is derived, and the scaling exponent (L∝Q0.44) is within the range of reported values from fieldwork in other regions.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/8991238','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/8991238"><span id="translatedtitle">Serological evidence of Lyme borreliosis in Africa: results from studies in <span class="hlt">Dar</span> es Salaam, Tanzania.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Mhalu, F S; Matre, R</p> <p>1996-09-01</p> <p>Investigations were performed on sera from blood donors, pregnant women, patients with polyarthritis and from patients with clinical suspicion of syphilis in <span class="hlt">Dar</span> es Salaam using Borrelia burgdorferi (Bb) flagellar antigen in a second generation ELISA test from DAKO A/S, Denmark, for specific IgM or IgG antibodies. An IgM and or IgG seropositivity rate of 30/100 (30%), 19/50 (7.2%), 10/20 (50%) and 11/20 (55%) was found in sera from the respective groups. These results compare with a Bb seroprevalence rate of 4/100 (4%), 1/52 (2%) and 363/5024 (7.2%) in blood donors, in pregnant women and in patients investigated serologically for Lyme borreliosis (Lb) respectively in Bergen, Norway, where cases of Lb are detected regularly. The high prevalence of antibodies to Bb flagellar antigen in <span class="hlt">Dar</span> es Salaam, Tanzania where clinical conditions including erythema migrans, arthritis, mycocarditis and CNS diseases as well as tickbites are found call for further clinical, entomological and laboratory investigations. PMID:8991238</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/27560962','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/27560962"><span id="translatedtitle">Identifying Ancient Settlement Patterns through Li<span class="hlt">DAR</span> in the Mosquitia Region of Honduras.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Fisher, Christopher T; Fernández-Diaz, Juan Carlos; Cohen, Anna S; Neil Cruz, Oscar; Gonzáles, Alicia M; Leisz, Stephen J; Pezzutti, Florencia; Shrestha, Ramesh; Carter, William</p> <p>2016-01-01</p> <p>The Mosquitia ecosystem of Honduras occupies the fulcrum between the American continents and as such constitutes a critical region for understanding past patterns of socio-political development and interaction. Heavy vegetation, rugged topography, and remoteness have limited scientific investigation. This paper presents prehistoric patterns of settlement and landuse for a critical valley within the Mosquitia derived from airborne Li<span class="hlt">DAR</span> scanning and field investigation. We show that (i) though today the valley is a wilderness it was densely inhabited in the past; (ii) that this population was organized into a three-tiered system composed of 19 settlements dominated by a city; and, (iii) that this occupation was embedded within a human engineered landscape. We also add to a growing body of literature that demonstrates the utility of Li<span class="hlt">DAR</span> as means for rapid cultural assessments in undocumented regions for analysis and conservation. Our ultimate hope is for our work to promote protections to safeguard the unique and critically endangered Mosquitia ecosystem and other similar areas in need of preservation. PMID:27560962</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2008AGUFM.G53A0630P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2008AGUFM.G53A0630P"><span id="translatedtitle">GeoEarthScope Airborne Li<span class="hlt">DAR</span> and Satellite InSAR Imagery</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Phillips, D. A.; Jackson, M. E.; Meertens, C.</p> <p>2008-12-01</p> <p>UNAVCO has successfully acquired a significant volume of aerial and satellite geodetic imagery as part of GeoEarthScope, a component of the EarthScope Facility project funded by the National Science Foundation. All GeoEarthScope acquisition activities are now complete. Airborne Li<span class="hlt">DAR</span> data acquisitions took place in 2007 and 2008 and cover a total area of more than 5000 square kilometers. The primary Li<span class="hlt">DAR</span> survey regions cover features in Northern California, Southern/Eastern California, the Pacific Northwest, the Intermountain Seismic Belt (including the Wasatch and Teton faults and Yellowstone), and Alaska. We have ordered and archived more than 28,000 scenes (more than 81,000 frames) of synthetic aperture radar (SAR) data suitable for interferometric analyses covering most of the western U.S. and parts of Alaska and Hawaii from several satellite platforms, including ERS-1/2, ENVISAT and RADARSAT. In addition to ordering data from existing archives, we also tasked the ESA ENVISAT satellite to acquire new SAR data in 2007 and 2008. GeoEarthScope activities were led by UNAVCO, guided by the community and conducted in partnership with the USGS and NASA. Processed imagery products, in addition to formats intended for use in standard research software, can also be viewed using general purpose tools such as Google Earth. We present a summary of these vast geodetic imagery datasets, totaling tens of terabytes, which are freely available to the community.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012AGUFM.H21B1180S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012AGUFM.H21B1180S"><span id="translatedtitle">Assessing riparian shade for the Lemhi River, Idaho using Li<span class="hlt">DAR</span>: A point cloud analysis</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Spaete, L.; Glenn, N. F.; Shrestha, R.; Shumar, M. L.; Mitchell, J.</p> <p>2012-12-01</p> <p>Riparian vegetation plays a crucial role in shading streams by reducing the amount of incoming solar insolation that would otherwise reach the water surface, negatively affecting water temperature and photosynthetic organisms within the water column. Unlike incoming solar insolation, riparian shade can be manipulated by adding or removing riparian vegetation, making it attractive for restoration as well as thermal credit trading programs. Before riparian shade can be evaluated in such trading programs, the existing riparian vegetation needs to be quantified. Several studies have investigated the utility of Li<span class="hlt">DAR</span> derived canopy height models for estimating riparian shade, however, few to no studies have used point cloud data as a direct model input in order to improve the riparian shade estimates. Using point cloud data increases spatial resolution and the ability to extract vegetation shape information without losses due to interpolation/rasterization. In this study, we assessed the ability of Li<span class="hlt">DAR</span> point cloud data to estimate riparian shade for 32 km of the Lemhi River in north central Idaho. Riparian shade quantification of the point cloud and canopy height models are compared to shade values calculated using established models in practice.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2016ISPAr41B3..669P&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2016ISPAr41B3..669P&link_type=ABSTRACT"><span id="translatedtitle">Building Change Detection by Combining Li<span class="hlt">DAR</span> Data and Ortho Image</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Peng, Daifeng; Zhang, Yongjun</p> <p>2016-06-01</p> <p>The elevation information is not considered in the traditional building change detection methods. This paper presents an algorithm of combining Li<span class="hlt">DAR</span> data and ortho image for 3D building change detection. The advantages of the proposed approach lie in the fusion of the height and spectral information by thematic segmentation. Furthermore, the proposed method also combines the advantages of pixel-level and object-level change detection by image differencing and object analysis. Firstly, two periods of Li<span class="hlt">DAR</span> data are filtered and interpolated to generate their corresponding DSMs. Secondly, a binary image of the changed areas is generated by means of differencing and filtering the two DSMs, and then thematic layer is generated and projected onto the DSMs and DOMs. Thirdly, geometric and spectral features of the changed area are calculated, which is followed by decision tree classification for the purpose of extracting the changed building areas. Finally, the statistics of the elevation and area change information as well as the change type of the changed buildings are done for building change analysis. Experimental results show that the completeness and correctness of building change detection are close to 81.8% and 85.7% respectively when the building area is larger than 80 m2, which are increased about 10% when compared with using ortho image alone.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2014E%26ES...17a2178X&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2014E%26ES...17a2178X&link_type=ABSTRACT"><span id="translatedtitle">A comprehensive framework of building model reconstruction from airborne Li<span class="hlt">DAR</span> data</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Xiao, Y.; Wang, C.; Xi, X. H.; Zhang, W. M.</p> <p>2014-03-01</p> <p>This paper presents a comprehensive framework of reconstructing 3D building models from airborne Li<span class="hlt">DAR</span> data, which involves building extraction, roof segmentation and model generation. Firstly, building points are extracted from Li<span class="hlt">DAR</span> point clouds by removing walls, trees, ground and noises. Walls and trees are identified by the normal and multi-return features respectively and then ground and noise are detected by the region growing algorithm which aims at extracting smooth surfaces. Then the connected component analysis is performed to extract building points. Secondly, once the building points are acquired, building roofs are separated by the region growing algorithm which employs the normal vector and curvature of points to detect planar clusters. Finally, by combining regular building outlines obtained from building points and roof intersections acquired from the roof segmentation results, 3D building models with high accuracy are derived. Experimental results demonstrate that the proposed method is able to correctly obtain building points and reconstruct 3D building models with high accuracy.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4541902','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4541902"><span id="translatedtitle">Li<span class="hlt">DAR</span> Scan Matching Aided Inertial Navigation System in GNSS-Denied Environments</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Tang, Jian; Chen, Yuwei; Niu, Xiaoji; Wang, Li; Chen, Liang; Liu, Jingbin; Shi, Chuang; Hyyppä, Juha</p> <p>2015-01-01</p> <p>A new scan that matches an aided Inertial Navigation System (INS) with a low-cost Li<span class="hlt">DAR</span> is proposed as an alternative to GNSS-based navigation systems in GNSS-degraded or -denied environments such as indoor areas, dense forests, or urban canyons. In these areas, INS-based Dead Reckoning (DR) and Simultaneous Localization and Mapping (SLAM) technologies are normally used to estimate positions as separate tools. However, there are critical implementation problems with each standalone system. The drift errors of velocity, position, and heading angles in an INS will accumulate over time, and on-line calibration is a must for sustaining positioning accuracy. SLAM performance is poor in featureless environments where the matching errors can significantly increase. Each standalone positioning method cannot offer a sustainable navigation solution with acceptable accuracy. This paper integrates two complementary technologies—INS and Li<span class="hlt">DAR</span> SLAM—into one navigation frame with a loosely coupled Extended Kalman Filter (EKF) to use the advantages and overcome the drawbacks of each system to establish a stable long-term navigation process. Static and dynamic field tests were carried out with a self-developed Unmanned Ground Vehicle (UGV) platform—NAVIS. The results prove that the proposed approach can provide positioning accuracy at the centimetre level for long-term operations, even in a featureless indoor environment. PMID:26184206</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013SPIE.8731E..0AS','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013SPIE.8731E..0AS"><span id="translatedtitle">Point Spread Function (PSF) noise filter strategy for geiger mode Li<span class="hlt">DAR</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Smith, O'Neil; Stark, Robert; Smith, Philip; St. Romain, Randall; Blask, Steven</p> <p>2013-05-01</p> <p>Li<span class="hlt">DAR</span> is an efficient optical remote sensing technology that has application in geography, forestry, and defense. The effectiveness is often limited by signal-to-noise ratio (SNR). Geiger mode avalanche photodiode (APD) detectors are able to operate above critical voltage, and a single photoelectron can initiate the current surge, making the device very sensitive. These advantages come at the expense of requiring computationally intensive noise filtering techniques. Noise is a problem which affects the imaging system and reduces the capability. Common noise-reduction algorithms have drawbacks such as over aggressive filtering, or decimating in order to improve quality and performance. In recent years, there has been growing interest on GPUs (Graphics Processing Units) for their ability to perform powerful massive parallel processing. In this paper, we leverage this capability to reduce the processing latency. The Point Spread Function (PSF) filter algorithm is a local spatial measure that has been GPGPU accelerated. The idea is to use a kernel density estimation technique for point clustering. We associate a local likelihood measure with every point of the input data capturing the probability that a 3D point is true target-return photons or noise (background photons, dark-current). This process suppresses noise and allows for detection of outliers. We apply this approach to the Li<span class="hlt">DAR</span> noise filtering problem for which we have recognized a speed-up factor of 30-50 times compared to traditional sequential CPU implementation.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/27338416','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/27338416"><span id="translatedtitle">Indirect Correspondence-Based Robust Extrinsic Calibration of Li<span class="hlt">DAR</span> and Camera.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Sim, Sungdae; Sock, Juil; Kwak, Kiho</p> <p>2016-01-01</p> <p>Li<span class="hlt">DAR</span> and cameras have been broadly utilized in computer vision and autonomous vehicle applications. However, in order to convert data between the local coordinate systems, we must estimate the rigid body transformation between the sensors. In this paper, we propose a robust extrinsic calibration algorithm that can be implemented easily and has small calibration error. The extrinsic calibration parameters are estimated by minimizing the distance between corresponding features projected onto the image plane. The features are edge and centerline features on a v-shaped calibration target. The proposed algorithm contributes two ways to improve the calibration accuracy. First, we use different weights to distance between a point and a line feature according to the correspondence accuracy of the features. Second, we apply a penalizing function to exclude the influence of outliers in the calibration datasets. Additionally, based on our robust calibration approach for a single Li<span class="hlt">DAR</span>-camera pair, we introduce a joint calibration that estimates the extrinsic parameters of multiple sensors at once by minimizing one objective function with loop closing constraints. We conduct several experiments to evaluate the performance of our extrinsic calibration algorithm. The experimental results show that our calibration method has better performance than the other approaches. PMID:27338416</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://pubs.er.usgs.gov/publication/70034055','USGSPUBS'); return false;" href="http://pubs.er.usgs.gov/publication/70034055"><span id="translatedtitle">Li<span class="hlt">DAR</span>-Assisted identification of an active fault near Truckee, California</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Hunter, L.E.; Howle, J.F.; Rose, R.S.; Bawden, G.W.</p> <p>2011-01-01</p> <p>We use high-resolution (1.5-2.4 points/m2) bare-earth airborne Light Detection and Ranging (Li<span class="hlt">DAR</span>) imagery to identify, map, constrain, and visualize fault-related geomorphology in densely vegetated terrain surrounding Martis Creek Dam near Truckee, California. Bare-earth Li<span class="hlt">DAR</span> imagery reveals a previously unrecognized and apparently youthful right-lateral strike-slip fault that exhibits laterally continuous tectonic geomorphic features over a 35-km-long zone. If these interpretations are correct, the fault, herein named the Polaris fault, may represent a significant seismic hazard to the greater Truckee-Lake Tahoe and Reno-Carson City regions. Three-dimensional modeling of an offset late Quaternary terrace riser indicates a minimum tectonic slip rate of 0.4 ?? 0.1 mm/yr.Mapped fault patterns are fairly typical of regional patterns elsewhere in the northern Walker Lane and are in strong coherence with moderate magnitude historical seismicity of the immediate area, as well as the current regional stress regime. Based on a range of surface-rupture lengths and depths to the base of the seismogenic zone, we estimate a maximum earthquake magnitude (M) for the Polaris fault to be between 6.4 and 6.9.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li class="active"><span>21</span></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_21 --> <div id="page_22" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li class="active"><span>22</span></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li><a href="#" onclick='return showDiv("page_24");'>24</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="421"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016JPRS..117...79Z','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016JPRS..117...79Z"><span id="translatedtitle">Improved progressive TIN densification filtering algorithm for airborne Li<span class="hlt">DAR</span> data in forested areas</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Zhao, Xiaoqian; Guo, Qinghua; Su, Yanjun; Xue, Baolin</p> <p>2016-07-01</p> <p>Filtering of light detection and ranging (Li<span class="hlt">DAR</span>) data into the ground and non-ground points is a fundamental step in processing raw airborne Li<span class="hlt">DAR</span> data. This paper proposes an improved progressive triangulated irregular network (TIN) densification (IPTD) filtering algorithm that can cope with a variety of forested landscapes, particularly both topographically and environmentally complex regions. The IPTD filtering algorithm consists of three steps: (1) acquiring potential ground seed points using the morphological method; (2) obtaining accurate ground seed points; and (3) building a TIN-based model and iteratively densifying TIN. The IPTD filtering algorithm was tested in 15 forested sites with various terrains (i.e., elevation and slope) and vegetation conditions (i.e., canopy cover and tree height), and was compared with seven other commonly used filtering algorithms (including morphology-based, slope-based, and interpolation-based filtering algorithms). Results show that the IPTD achieves the highest filtering accuracy for nine of the 15 sites. In general, it outperforms the other filtering algorithms, yielding the lowest average total error of 3.15% and the highest average kappa coefficient of 89.53%.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2008AGUFMOS11F..06R&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2008AGUFMOS11F..06R&link_type=ABSTRACT"><span id="translatedtitle">An Airborne Scanning Li<span class="hlt">DAR</span> System for Ocean and Coastal Applications</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Reineman, B. D.; Lenain, L.; Castel, D.; Melville, W. K.</p> <p>2008-12-01</p> <p>We have developed an airborne scanning Li<span class="hlt">DAR</span> (Light Detection And Ranging) system and demonstrated its functionality for terrestrial and oceanographic measurements. Differential GPS (DGPS) and an Inertial Navigation System (INS) are synchronized with the Li<span class="hlt">DAR</span>, providing end result vertical rms errors of approximately 6~cm. Flying 170~m above the surface, we achieve a point density of ~ 0.7 m-2 and a swath width of 90 to 120~m over ocean and 200~m over land. Georeferencing algorithms were developed in-house and earth-referenced data are available several hours after acquisition. Surveys from the system are compared with ground DGPS surveys and existing airborne surveys of fixed targets. Twelve research flights in a Piper Twin Comanche from August 2007 to July 2008 have provided topography of the Southern California coastline and sea surface wave fields in the nearshore ocean environment. Two of the flights also documented the results of the October 2007 landslide on Mt.~Soledad in La Jolla, California. Eight research flights aboard a Cessna Caravan surveyed the topography, lagoon, reef, and surrounding seas of Lady Elliot Island (LEI) in Australia's Great Barrier Reef in April 2008. We describe applications for the system, including coastal topographic surveys, wave measurements, reef research, and ship wake studies.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014AGUFMEP43E..06G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014AGUFMEP43E..06G"><span id="translatedtitle">Improving Aboveground Carbon Estimates in Dryland Ecosystems with Airborne Li<span class="hlt">DAR</span> and Satellite Laser Altimetry</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Glenn, N. F.; Shrestha, R.; Li, A.; Spaete, L.</p> <p>2014-12-01</p> <p>Numerous studies have demonstrated the utility of ground and airborne Li<span class="hlt">DAR</span> data to quantify ecosystem structure. In addition, data from satellite-based laser altimetry (e.g. ICESat's GLAS instrument) have been used to estimate vegetation heights, aboveground carbon, and topography in forested areas. With the upcoming ICESAT-2 satellite scheduled to launch in 2017, we have the potential to map vegetation characteristics and dynamics in other ecosystems, including semiarid and low-height ecosystems, at global and regional scales. The ICESat-2 satellite will include the Advanced Topographic Laser Altimeter System (ATLAS) with a configuration of 6 laser beams with 532 nm wavelength and photon counting detectors. We will demonstrate the potential of ICESat-2 to provide estimates of vegetation structure and topography in a dryland ecosystem by simulating the configuration of the ATLAS mission. We will also examine how airborne Li<span class="hlt">DAR</span> can be used together with ICESat-2 and other satellite data to achieve estimates of aboveground carbon. We will explore how these data may be used for future monitoring and quantification of spatial and temporal changes in aboveground carbon and topography.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2009AGUFMIN51C..06N','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2009AGUFMIN51C..06N"><span id="translatedtitle">Processing Large Li<span class="hlt">DAR</span> datasets for Forest Canopy Metrics Using 64-bit GRASS GIS (Invited)</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Newcomb, D.; Mitasova, H.</p> <p>2009-12-01</p> <p>The flooding impacts of tropical storm events in 1999 inspired the statewide collection of Li<span class="hlt">DAR</span> data in the State of North Carolina, USA, in three phases between 2001 and 2006, for the purpose of floodplain mapping. This data collection effort generated more than 800 GB of multiple return Li<span class="hlt">DAR</span> data. Using native 64-bit GRASS on 64-bit Centos Linux, forest canopy heights and other structural metrics were generated on a 18.2 m (60 foot) grid for the entire State of North Carolina from ASCII x,y,z datasets ranging in size from 9GB to 379 GB using binning techniques to calculate max, min, and standard deviation statistical measures for each grid cell using tools available in GRASS 6.3-6.4 to derive initial canopy heights. Data processing time for each file ranged from less than 1 hour hr ( 9 GB) to 15 hrs (379 GB). Data from the 6.1m (20ft) elevation grid generated for the floodplain mapping project was analyzed using neighborhood analysis to correct for the effects of land surface change within each 18.2m (60 ft) cell. Canopy heights up to 76.2m (249 ft) were calculated and the raster data sets were aggregated to a grid with 17237 Rows and 45102 columns . Histograms of canopy height data were derived from buffered known locations of bird nesting habitat for birds with differing canopy requirements.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4372933','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4372933"><span id="translatedtitle">Body-Art Practices Among Undergraduate Medical University Students in <span class="hlt">Dar</span> Es Salaam, Tanzania, 2014</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Chacha, Chacha Emmanuel; Kazaura, Method R.</p> <p>2015-01-01</p> <p>Background: Body-art practices are increasing among adolescents and young adults. Although substantial data are available in developed countries, little has been documented about body-art practices in developing countries. Objective: To determine the magnitude, types and reasons for practicing body-art practices among undergraduate medical University students in <span class="hlt">Dar</span> es Salaam, Tanzania. Materials and Methods: A cross-sectional descriptive study was conducteed among undergraduate University students in <span class="hlt">Dar</span> es Salaam involving 536 respondents from two Universities. We used a self-administered questionnaire to collect data. Analyses were based on summary measures and bivariate analyses. Results: While 7.5% of undergraduate students reported having tattoos, 20% reported having body puncturing or piercing. Body piercing is reported more among female university undergraduate students than their male counterparts. Reported main reasons for undergoing body-art include “a mark of beauty,” 24%, “just wanted one,” 18% and “a mark of femininity or masculinity,” 17%. The majority (98%) of students were aware that unsafe body-art practices may lead to contracting HIV and more than half (52%) reported awareness of the risk of Hepatitis B infection. Conclusions: Despite high awareness of the potential risks involved in unsafe body arts that include tattoo and piercing, these practices are increasing among adolescents and young adults. There is need to have educational and counseling efforts so as to minimize associated health risks. PMID:25814729</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/26941756','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/26941756"><span id="translatedtitle">Characterizing Croatian Wheat Germplasm Diversity and Structure in a European Context by <span class="hlt">DAr</span>T Markers.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Novoselović, Dario; Bentley, Alison R; Šimek, Ruđer; Dvojković, Krešimir; Sorrells, Mark E; Gosman, Nicolas; Horsnell, Richard; Drezner, Georg; Šatović, Zlatko</p> <p>2016-01-01</p> <p>Narrowing the genetic base available for future genetic progress is a major concern to plant breeders. In order to avoid this, strategies to characterize and protect genetic diversity in regional breeding pools are required. In this study, 89 winter wheat cultivars released in Croatia between 1936 and 2006 were genotyped using 1,229 <span class="hlt">DAr</span>T (diversity array technology) markers to assess the diversity and population structure. In order to place Croatian breeding pool (CBP) in a European context, Croatian wheat cultivars were compared to 523 European cultivars from seven countries using a total of 166 common <span class="hlt">DAr</span>T markers. The results show higher genetic diversity in the wheat breeding pool from Central Europe (CE) as compared to that from Northern and Western European (NWE) countries. The most of the genetic diversity was attributable to the differences among cultivars within countries. When the geographical criterion (CE vs. NWE) was applied, highly significant difference between regions was obtained that accounted for 16.19% of the total variance, revealing that the CBP represents genetic variation not currently captured in elite European wheat. The current study emphasizes the important contribution made by plant breeders to maintaining wheat genetic diversity and suggests that regional breeding is essential to the maintenance of this diversity. The usefulness of open-access wheat datasets is also highlighted. PMID:26941756</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2016SPIE.9901E..0AW&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2016SPIE.9901E..0AW&link_type=ABSTRACT"><span id="translatedtitle">Road traffic sign detection and classification from mobile Li<span class="hlt">DAR</span> point clouds</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Weng, Shengxia; Li, Jonathan; Chen, Yiping; Wang, Cheng</p> <p>2016-03-01</p> <p>Traffic signs are important roadway assets that provide valuable information of the road for drivers to make safer and easier driving behaviors. Due to the development of mobile mapping systems that can efficiently acquire dense point clouds along the road, automated detection and recognition of road assets has been an important research issue. This paper deals with the detection and classification of traffic signs in outdoor environments using mobile light detection and ranging (Li- <span class="hlt">DAR</span>) and inertial navigation technologies. The proposed method contains two main steps. It starts with an initial detection of traffic signs based on the intensity attributes of point clouds, as the traffic signs are always painted with highly reflective materials. Then, the classification of traffic signs is achieved based on the geometric shape and the pairwise 3D shape context. Some results and performance analyses are provided to show the effectiveness and limits of the proposed method. The experimental results demonstrate the feasibility and effectiveness of the proposed method in detecting and classifying traffic signs from mobile Li<span class="hlt">DAR</span> point clouds.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4934358','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4934358"><span id="translatedtitle">Indirect Correspondence-Based Robust Extrinsic Calibration of Li<span class="hlt">DAR</span> and Camera</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Sim, Sungdae; Sock, Juil; Kwak, Kiho</p> <p>2016-01-01</p> <p>Li<span class="hlt">DAR</span> and cameras have been broadly utilized in computer vision and autonomous vehicle applications. However, in order to convert data between the local coordinate systems, we must estimate the rigid body transformation between the sensors. In this paper, we propose a robust extrinsic calibration algorithm that can be implemented easily and has small calibration error. The extrinsic calibration parameters are estimated by minimizing the distance between corresponding features projected onto the image plane. The features are edge and centerline features on a v-shaped calibration target. The proposed algorithm contributes two ways to improve the calibration accuracy. First, we use different weights to distance between a point and a line feature according to the correspondence accuracy of the features. Second, we apply a penalizing function to exclude the influence of outliers in the calibration datasets. Additionally, based on our robust calibration approach for a single Li<span class="hlt">DAR</span>-camera pair, we introduce a joint calibration that estimates the extrinsic parameters of multiple sensors at once by minimizing one objective function with loop closing constraints. We conduct several experiments to evaluate the performance of our extrinsic calibration algorithm. The experimental results show that our calibration method has better performance than the other approaches. PMID:27338416</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/26184206','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/26184206"><span id="translatedtitle">Li<span class="hlt">DAR</span> Scan Matching Aided Inertial Navigation System in GNSS-Denied Environments.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Tang, Jian; Chen, Yuwei; Niu, Xiaoji; Wang, Li; Chen, Liang; Liu, Jingbin; Shi, Chuang; Hyyppä, Juha</p> <p>2015-01-01</p> <p>A new scan that matches an aided Inertial Navigation System (INS) with a low-cost Li<span class="hlt">DAR</span> is proposed as an alternative to GNSS-based navigation systems in GNSS-degraded or -denied environments such as indoor areas, dense forests, or urban canyons. In these areas, INS-based Dead Reckoning (DR) and Simultaneous Localization and Mapping (SLAM) technologies are normally used to estimate positions as separate tools. However, there are critical implementation problems with each standalone system. The drift errors of velocity, position, and heading angles in an INS will accumulate over time, and on-line calibration is a must for sustaining positioning accuracy. SLAM performance is poor in featureless environments where the matching errors can significantly increase. Each standalone positioning method cannot offer a sustainable navigation solution with acceptable accuracy. This paper integrates two complementary technologies-INS and Li<span class="hlt">DAR</span> SLAM-into one navigation frame with a loosely coupled Extended Kalman Filter (EKF) to use the advantages and overcome the drawbacks of each system to establish a stable long-term navigation process. Static and dynamic field tests were carried out with a self-developed Unmanned Ground Vehicle (UGV) platform-NAVIS. The results prove that the proposed approach can provide positioning accuracy at the centimetre level for long-term operations, even in a featureless indoor environment. PMID:26184206</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/24908469','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/24908469"><span id="translatedtitle">The use of social media among adolescents in <span class="hlt">Dar</span> es Salaam and Mtwara, Tanzania.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Pfeiffer, Constanze; Kleeb, Matthis; Mbelwa, Alice; Ahorlu, Collins</p> <p>2014-05-01</p> <p>Social media form part of the rapid worldwide digital development that is re-shaping the life of many young people. While the use of social media by youths is increasingly researched in the North, studies about youth in the South are missing. It therefore remains unclear how social media can be included in interventions that aim at informing young people in many countries of the global South about sexual and reproductive health. This paper presents findings of a mixed-methods study of young people's user behaviour on the internet and specifically of social media as a platform for sexual health promotion in Tanzania. The study used questionnaires with 60 adolescents and in-depth interviews with eight students aged 15 to 19 years in <span class="hlt">Dar</span> es Salaam, and in Mtwara, Southern Tanzania. Findings show that youth in <span class="hlt">Dar</span> es Salaam and Mtwara access the internet mainly through mobile phones. Facebook is by far the most popular internet site. Adolescents highlighted their interest in reproductive and sexual health messages and updates being delivered through humorous posts, links and clips, as well as by youth role models like music stars and actors that are entertaining and reflect up-to-date trends of modern youth culture. PMID:24908469</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015OptLT..70...63R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015OptLT..70...63R"><span id="translatedtitle">Automatic detection of zebra crossings from mobile Li<span class="hlt">DAR</span> data</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Riveiro, B.; González-Jorge, H.; Martínez-Sánchez, J.; Díaz-Vilariño, L.; Arias, P.</p> <p>2015-07-01</p> <p>An algorithm for the automatic detection of zebra crossings from mobile Li<span class="hlt">DAR</span> data is developed and tested to be applied for road management purposes. The algorithm consists of several subsequent processes starting with road segmentation by performing a curvature analysis for each laser cycle. Then, intensity images are created from the point cloud using rasterization techniques, in order to detect zebra crossing using the Standard Hough Transform and logical constrains. To optimize the results, image processing algorithms are applied to the intensity images from the point cloud. These algorithms include binarization to separate the painting area from the rest of the pavement, median filtering to avoid noisy points, and mathematical morphology to fill the gaps between the pixels in the border of white marks. Once the road marking is detected, its position is calculated. This information is valuable for inventorying purposes of road managers that use Geographic Information Systems. The performance of the algorithm has been evaluated over several mobile Li<span class="hlt">DAR</span> strips accounting for a total of 30 zebra crossings. That test showed a completeness of 83%. Non-detected marks mainly come from painting deterioration of the zebra crossing or by occlusions in the point cloud produced by other vehicles on the road.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014AGUFM.B51C0047L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014AGUFM.B51C0047L"><span id="translatedtitle">Tree Crown Delineation using Watershed Techniques and Forest Metrics from NEON Li<span class="hlt">DAR</span> Data</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Luong, K. Y.</p> <p>2014-12-01</p> <p>Li<span class="hlt">DAR</span> is a powerful remote sensing tool allowing for forest metrics to be taken on varying scales, which ultimately provide important forestry variables used to calculate factors such as total biomass or leaf area index. These variables are most useful when calculated for individual trees throughout a stand, but in very dense forests, identifying single trees becomes more difficult by traditional means. Full forests can be quantified uniquely for the best understanding of ecological contributions as opposed to purely in situ tree inventories which are time consuming and extremely localized. Canopy height models (CHM) can be used to understand the forest as a whole. By inverting the CHM, the tree data becomes sinks in the ground, mimicking ponds; by applying watershed-related spatial analyst tools in ArcGIS and GrassGIS, the trees are delineated by makeshift "flooding." Within this algorithm, the crown peaks are also extracted as an intermediate step to delineation, but this is a reliable means to obtain an accurate number of trees, as well as their individual heights with high reliability (R2 = 0.87). Delineated tree polygons can be directly overlaid onto different rasters to get many forest variables. In tightly clustered and very sparse stands, this method of delineation has a high level of accuracy. Following the workflow studies conducted on NEON Li<span class="hlt">DAR</span> data on the Soaproot Saddle site, a ground-truth comparison was made with the Teakettle Experimental Forest site due to the availability of tree inventory data.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014E%26ES...17a2252L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014E%26ES...17a2252L"><span id="translatedtitle">Use of Airborne Li<span class="hlt">DAR</span> To Estimate Forest Stand Characteristics</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Li, Qi; Zhou, Wei; Li, Chang</p> <p>2014-03-01</p> <p>Small-Footprint Airborne Li<span class="hlt">DAR</span>(light detection and ranging) remote sensing is a breakthrough technology for deriving forest canopy structural characteristics. Because the technique is relatively new as applied to canopy measurement in China, there is a tremendous need for experiments that integrate field work, Li<span class="hlt">DAR</span> remote sensing and subsequent analyses for retrieving the full complement of structural measures critical for forestry applications. Data storage capacity and high processing speed available today have made it possible to digitally sample and store the entire reflected waveform, instead of only extracting the discrete coordinates which form the so-called point clouds. Return waveforms can give more detailed insights into the vertical structure of surface objects, surface slope, roughness and reflectivity than the conventional echoes. In this paper, an improved Expectation Maximum (EM) algorithm is adopted to decompose raw waveform data. Derived forest biophysical parameters, such as vegetation height, subcanopy topography, crown volume, ground reflectivity, vegetation reflectivity and canopy closure, are able to describe the horizontal and vertical forest canopy structure.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013MeScT..24i5402K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013MeScT..24i5402K"><span id="translatedtitle">A new method for building roof segmentation from airborne Li<span class="hlt">DAR</span> point cloud data</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kong, Deming; Xu, Lijun; Li, Xiaolu</p> <p>2013-09-01</p> <p>A new method based on the combination of two kinds of clustering algorithms for building roof segmentation from airborne Li<span class="hlt">DAR</span> (light detection and ranging) point cloud data is proposed. The K-plane algorithm is introduced to classify the laser footprints that cannot be correctly classified by the traditional K-means algorithm. High-precision classification can be obtained by combining the two aforementioned clustering algorithms. Furthermore, to improve the performance of the new segmentation method, a new initialization method is proposed to acquire the number and coordinates of the initial cluster centers for the K-means algorithm. In the proposed initialization method, the geometrical planes of a building roof are estimated from the elevation image of the building roof by using the mathematical morphology and Hough transform techniques. By calculating the number and normal vectors of the estimated geometrical planes, the number and coordinates of the initial cluster centers for the K-means algorithm are obtained. With the aid of the proposed initialization and segmentation methods, the point cloud of the building roof can be rapidly and appropriately classified. The proposed methods are validated by using both simulated and real Li<span class="hlt">DAR</span> data.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010AGUFM.H11G0889W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010AGUFM.H11G0889W"><span id="translatedtitle">Estimating Water Storage in Prairie Wetlands from a Li<span class="hlt">DAR</span> DEM</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Westbrook, C. J.; Minke, A. G.; Pomeroy, J. W.; Guo, X.</p> <p>2010-12-01</p> <p>The Prairie Pothole Region (PPR) of North America contains millions of wetlands in shallow depressions that have potential to store a significant volume of surface water. Assessing and modeling the effect of wetland storage on streamflow requires accurate methods to quantify wetland water volume. Currently, many methods rely on utilizing the strong statistical relationships between area (A), volume (V), and depth (h) to estimate wetland storage. While V-A equations are commonly used throughout the PPR, equations that utilize the V-A-h relationship are not used extensively because detailed topographic data are required. This paper suggests a new approach for implementing V-A-h relationships to determine wetland volume from wetland characteristics extracted from a high resolution Li<span class="hlt">DAR</span> digital elevation model. GIS analysis was used to generate elevation contours that represent potential surface areas measurements, as well as provide a measure of the change in area with depth. This data collection process was also automated to generate the necessary input for estimating volume through the V-A-h equations. These volumes were compared to estimates from two V-A equations commonly used in the PPR. Results demonstrate that the automated Li<span class="hlt">DAR</span> V-A-h method provided a better estimate of wetland volume than the V-A equations. This new method could be useful in quantifying the capacity of prairie pothole wetlands to store water and modeling their role in attenuating streamflows at a variety of spatial scales.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2013ThApC.114..213N&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2013ThApC.114..213N&link_type=ABSTRACT"><span id="translatedtitle">Basic analysis of climate and urban bioclimate of <span class="hlt">Dar</span> es Salaam, Tanzania</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Ndetto, Emmanuel L.; Matzarakis, Andreas</p> <p>2013-10-01</p> <p>Better understanding of urban microclimate and bioclimate of any city is imperative today when the world is constrained by both urbanisation and global climate change. Urbanisation generally triggers changes in land cover and hence influencing the urban local climate. <span class="hlt">Dar</span> es Salaam city in Tanzania is one of the fast growing cities. Assessment of its urban climate and the human biometeorological conditions was done using the easily available synoptic meteorological data covering the period 2001-2011. In particular, the physiologically equivalent temperature (PET) was calculated using the RayMan software and results reveal that the afternoon period from December to February (DJF season) is relatively the most thermal stressful period to human beings in <span class="hlt">Dar</span> es Salaam where PET values of above 35 °C were found. Additionally, the diurnal cycle of the individual meteorological elements that influence the PET index were analysed and found that air temperature of 30-35 °C dominate the afternoon period from 12:00 to 15:00 hours local standard time at about 60 % of occurrence. The current results, though considered as preliminary to the ongoing urban climate study in the city, provide an insight on how urban climate research is of significant importance in providing useful climatic information for ensuring quality of life and wellbeing of city dwellers.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012AGUFM.G23A0903K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012AGUFM.G23A0903K"><span id="translatedtitle">3-D earthquake surface displacements from differencing pre- and post-event Li<span class="hlt">DAR</span> point clouds</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Krishnan, A. K.; Nissen, E.; Arrowsmith, R.; Saripalli, S.</p> <p>2012-12-01</p> <p>The explosion in aerial Li<span class="hlt">DAR</span> surveying along active faults across the western United States and elsewhere provides a high-resolution topographic baseline against which to compare repeat Li<span class="hlt">DAR</span> datasets collected after future earthquakes. We present a new method for determining 3-D coseismic surface displacements and rotations by differencing pre- and post-earthquake Li<span class="hlt">DAR</span> point clouds using an adaptation of the Iterative Closest Point (ICP) algorithm, a point set registration technique widely used in medical imaging, computer vision and graphics. There is no need for any gridding or smoothing of the Li<span class="hlt">DAR</span> data and the method works well even with large mismatches in the density of the two point clouds. To explore the method's performance, we simulate pre- and post-event point clouds using real ("B4") Li<span class="hlt">DAR</span> data on the southern San Andreas Fault perturbed with displacements of known magnitude. For input point clouds with ~2 points per square meter, we are able to reproduce displacements with a 50 m grid spacing and with horizontal and vertical accuracies of ~20 cm and ~4 cm. In the future, finer grids and improved precisions should be possible with higher shot densities and better survey geo-referencing. By capturing near-fault deformation in 3-D, Li<span class="hlt">DAR</span> differencing with ICP will complement satellite-based techniques such as InSAR which map only certain components of the surface deformation and which often break down close to surface faulting or in areas of dense vegetation. It will be especially useful for mapping shallow fault slip and rupture zone deformation, helping inform paleoseismic studies and better constrain fault zone rheology. Because ICP can image rotations directly, the technique will also help resolve the detailed kinematics of distributed zones of faulting where block rotations may be common.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2009AGUFM.G51B0662G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2009AGUFM.G51B0662G"><span id="translatedtitle">Impact of survey workflow on precision and accuracy of terrestrial Li<span class="hlt">DAR</span> datasets</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Gold, P. O.; Cowgill, E.; Kreylos, O.</p> <p>2009-12-01</p> <p>Ground-based Li<span class="hlt">DAR</span> (Light Detection and Ranging) survey techniques are enabling remote visualization and quantitative analysis of geologic features at unprecedented levels of detail. For example, digital terrain models computed from Li<span class="hlt">DAR</span> data have been used to measure displaced landforms along active faults and to quantify fault-surface roughness. But how accurately do terrestrial Li<span class="hlt">DAR</span> data represent the true ground surface, and in particular, how internally consistent and precise are the mosaiced Li<span class="hlt">DAR</span> datasets from which surface models are constructed? Addressing this question is essential for designing survey workflows that capture the necessary level of accuracy for a given project while minimizing survey time and equipment, which is essential for effective surveying of remote sites. To address this problem, we seek to define a metric that quantifies how scan registration error changes as a function of survey workflow. Specifically, we are using a Trimble GX3D laser scanner to conduct a series of experimental surveys to quantify how common variables in field workflows impact the precision of scan registration. Primary variables we are testing include 1) use of an independently measured network of control points to locate scanner and target positions, 2) the number of known-point locations used to place the scanner and point clouds in 3-D space, 3) the type of target used to measure distances between the scanner and the known points, and 4) setting up the scanner over a known point as opposed to resectioning of known points. Precision of the registered point cloud is quantified using Trimble Realworks software by automatic calculation of registration errors (errors between locations of the same known points in different scans). Accuracy of the registered cloud (i.e., its ground-truth) will be measured in subsequent experiments. To obtain an independent measure of scan-registration errors and to better visualize the effects of these errors on a registered point</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013EGUGA..15.3930B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013EGUGA..15.3930B"><span id="translatedtitle">Modeling Urban Growth Spatial Dynamics: Case studies of Addis Ababa and <span class="hlt">Dar</span> es Salaam</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Buchta, Katja; Abo El Wafa, Hany; Printz, Andreas; Pauleit, Stephan</p> <p>2013-04-01</p> <p>Rapid urbanization, and consequently, the dramatic spatial expansion of mostly informal urban areas increases the vulnerability of African cities to the effects of climate change such as sea level rise, more frequent flooding, droughts and heat waves. The EU FP 7 funded project CLUVA (Climate Change and Urban Vulnerability in Africa, www.cluva.eu) aims to develop strategies for minimizing the risks of natural hazards caused by climate change and to improve the coping capacity of African cities. Green infrastructure may play a particular role in climate change adaptation by providing ecosystem services for flood protection, stormwater retention, heat island moderation and provision of food and fuel wood. In this context, a major challenge is to gain a better understanding of the spatial and temporal dynamics of the cities and how these impact on green infrastructure and hence their vulnerability. Urban growth scenarios for two African cities, namely Addis Ababa, Ethiopia and <span class="hlt">Dar</span> es Salaam, Tanzania, were developed based on a characterization of their urban morphology. A population growth driven - GIS based - disaggregation modeling approach was applied. Major impact factors influencing the urban dynamics were identified both from literature and interviews with local experts. Location based factors including proximity to road infrastructure and accessibility, and environmental factors including slope, surface and flood risk areas showed a particular impact on urban growth patterns. In Addis Ababa and <span class="hlt">Dar</span> es Salaam, population density scenarios were modeled comparing two housing development strategies. Results showed that a densification scenario significantly decreases the loss of agricultural and green areas such as forests, bushland and sports grounds. In <span class="hlt">Dar</span> es Salaam, the scenario of planned new settlements with a population density of max. 350 persons per hectare would lead until 2025 to a loss of agricultural land (-10.1%) and green areas (-6.6%). On the other</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2004GeCoA..68.2359G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2004GeCoA..68.2359G"><span id="translatedtitle">Petrology and shock metamorphism of the olivine-phyric <span class="hlt">shergottite</span> Yamato 980459 - Evidence for a two-stage cooling and a single-stage ejection history</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Greshake, Ansgar; Fritz, Jörg; Stöffler, Dieter</p> <p>2004-05-01</p> <p>The basaltic Martian meteorite Yamato 980459 consists of large olivine phenocrysts and often prismatic pyroxenes set into a fine-grained groundmass of smaller more Fe-rich olivine, chromite, and an interstitial residual material displaying quenching textures of dendritic olivine, chain-like augite and sulfide droplets in a glassy matrix. Yamato 980459 is, thus, the only Martian meteorite without plagioclase/maskelynite. Olivine is compositionally zoned from a Mg-rich core to a Fe-rich rim with the outer few micrometers being especially rich in iron. With Fo 84 the cores are the most magnesian olivines found in Martian meteorites so far. Pyroxenes are also mostly composite crystals of large orthopyroxene cores and thin Ca-rich overgrowths. Separate pigeonite and augites are rare. On basis of the mineral compositions, the cooling rates determined from crystal morphologies, and crystal grain size distributions it is deduced that the parent magma of Yamato 980459 initially cooled under near equilibrium conditions e.g., in a magma chamber allowing chromite and the Mg-rich silicates to form as cumulus phases. Fractional crystallization at higher cooling rates and a low degree of undercooling let to the formation of the Ca-, <span class="hlt">Al</span>-, and Fe-rich overgrowths on olivine and orthopyroxene while the magma was ascending towards the Martian surface. Finally and before plagioclase and also phosphates could precipitate, the magma was very quickly erupted quenching the remaining melt to glass, dendritic silicates and sulfide droplets. The shape preferred orientation of olivine and pyroxene suggests a quick, thin outflow of lava. According to the shock effects found in the minerals of Yamato 980459, the meteorite experienced an equilibration shock pressure of about 20-25 GPa. Its near surface position allowed the ejection from the planet's surface already by a single impact event and at relatively low shock pressures.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li class="active"><span>22</span></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li><a href="#" onclick='return showDiv("page_24");'>24</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_22 --> <div id="page_23" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li class="active"><span>23</span></li> <li><a href="#" onclick='return showDiv("page_24");'>24</a></li> <li><a href="#" onclick='return showDiv("page_25");'>25</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="441"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2015JSR...104....9Y&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2015JSR...104....9Y&link_type=ABSTRACT"><span id="translatedtitle">Measuring the effects of morphological changes to sea turtle nesting beaches over time with Li<span class="hlt">DAR</span> data</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Yamamoto, Kristina H.; Anderson, Sharolyn J.; Sutton, Paul C.</p> <p>2015-10-01</p> <p>Sea turtle nesting beaches in southeastern Florida were evaluated for changes from 1999 to 2005 using Li<span class="hlt">DAR</span> datasets. Changes to beach volume were correlated with changes in several elevation-derived characteristics, such as elevation and slope. In addition, these changes to beach geomorphology were correlated to changes in nest success, illustrating that beach alterations may affect sea turtle nesting behavior. The ability to use Li<span class="hlt">DAR</span> datasets to quickly and efficiently conduct beach comparisons for habitat use represents another benefit to this high spatial resolution data.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2014SPIE.9244E..0AD&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2014SPIE.9244E..0AD&link_type=ABSTRACT"><span id="translatedtitle">Three-dimensional building roof boundary extraction using high-resolution aerial image and Li<span class="hlt">DAR</span> data</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Dal Poz, A. P.; Fazan, Antonio J.</p> <p>2014-10-01</p> <p>This paper presents a semiautomatic method for rectilinear building roof boundary extraction, based on the integration of high-resolution aerial image and Li<span class="hlt">DAR</span> (Light Detection and Ranging) data. The proposed method is formulated as an optimization problem, in which a snakes-based objective function is developed to represent the building roof boundaries in an object-space coordinate system. Three-dimensional polylines representing building roof boundaries are obtained by optimizing the objective function using the dynamic programming optimization technique. The results of our experiments showed that the proposed method satisfactorily performed the task of extracting different building roof boundaries from aerial image and Li<span class="hlt">DAR</span> data.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3274126','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3274126"><span id="translatedtitle">Object-Based Integration of Photogrammetric and Li<span class="hlt">DAR</span> Data for Automated Generation of Complex Polyhedral Building Models</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Kim, Changjae; Habib, Ayman</p> <p>2009-01-01</p> <p>This research is concerned with a methodology for automated generation of polyhedral building models for complex structures, whose rooftops are bounded by straight lines. The process starts by utilizing Li<span class="hlt">DAR</span> data for building hypothesis generation and derivation of individual planar patches constituting building rooftops. Initial boundaries of these patches are then refined through the integration of Li<span class="hlt">DAR</span> and photogrammetric data and hierarchical processing of the planar patches. Building models for complex structures are finally produced using the refined boundaries. The performance of the developed methodology is evaluated through qualitative and quantitative analysis of the generated building models from real data. PMID:22346722</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011AGUFMEP41A0583S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011AGUFMEP41A0583S"><span id="translatedtitle">Quantification of L-band InSAR decorrelation in volcanic terrains using airborne Li<span class="hlt">DAR</span> data</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Sedze, M.; Heggy, E.; Jacquemoud, S.; Bretar, F.</p> <p>2011-12-01</p> <p>Repeat-pass InSAR LOS measurements of the Piton de La Fournaise (La Reunion Island, France) suffer from substantial phase decorrelation due to the occurrence of vegetation and ash deposits on the caldera and slopes of the edifice. To correct this deficiency, we combine normalized airborne Li<span class="hlt">DAR</span> (Light Detection and Ranging) intensity data with spaceborne InSAR coherence images from ALOS PALSAR L-band acquired over the volcano in 2008 and 2009, following the 2007 major eruption. The fusion of the two data sets improves the calculation of coherence and the textural classification of different volcanic surfaces. For future missions considering both InSAR and/or Li<span class="hlt">DAR</span> such as DESDynI (Deformation, Ecosystem Structure and Dynamics of Ice), such data fusion studies can provide a better analysis of the spatiotemporal variations in InSAR coherence in order to enhance the monitoring of pre-eruptive ground displacements. The airborne surveys conducted in 2008 and 2009, cover different types of vegetation and terrain roughness on the central and western parts of the volcano. The topographic data are first processed to generate a high-resolution digital terrain model (DTM) of the volcanic edifice with elevation accuracy better than 1 m. For our purposes, the phase variations caused by the surface relief can be eliminated using the Li<span class="hlt">DAR</span>-derived DTM. Then normalized Li<span class="hlt">DAR</span> intensities are correlated to the L-band polarimetric coherence for different zones of the volcano to assess the Li<span class="hlt">DAR</span>-InSAR statistical behavior of different lava flows, pyroclastics, and vegetated surfaces. Results suggest that each volcanic terrain type is characterized by a unique Li<span class="hlt">DAR</span>-InSAR histogram pattern. We identified four Li<span class="hlt">DAR</span>-InSAR distinguished relations: (1) pahoehoe lava flow surfaces show an agglomerate histogram pattern which may be explained by low surface scattering and low wave penetration into the geological medium; (2) eroded a'a lava surfaces is characterized by high standard deviation</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013AGUFM.B41E0459G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013AGUFM.B41E0459G"><span id="translatedtitle">Quantification of Li<span class="hlt">DAR</span> measurement uncertainty through propagation of errors due to sensor sub-systems and terrain morphology</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Goulden, T.; Hopkinson, C.</p> <p>2013-12-01</p> <p>The quantification of Li<span class="hlt">DAR</span> sensor measurement uncertainty is important for evaluating the quality of derived DEM products, compiling risk assessment of management decisions based from Li<span class="hlt">DAR</span> information, and enhancing Li<span class="hlt">DAR</span> mission planning capabilities. Current quality assurance estimates of Li<span class="hlt">DAR</span> measurement uncertainty are limited to post-survey empirical assessments or vendor estimates from commercial literature. Empirical evidence can provide valuable information for the performance of the sensor in validated areas; however, it cannot characterize the spatial distribution of measurement uncertainty throughout the extensive coverage of typical Li<span class="hlt">DAR</span> surveys. Vendor advertised error estimates are often restricted to strict and optimal survey conditions, resulting in idealized values. Numerical modeling of individual pulse uncertainty provides an alternative method for estimating Li<span class="hlt">DAR</span> measurement uncertainty. Li<span class="hlt">DAR</span> measurement uncertainty is theoretically assumed to fall into three distinct categories, 1) sensor sub-system errors, 2) terrain influences, and 3) vegetative influences. This research details the procedures for numerical modeling of measurement uncertainty from the sensor sub-system (GPS, IMU, laser scanner, laser ranger) and terrain influences. Results show that errors tend to increase as the laser scan angle, altitude or laser beam incidence angle increase. An experimental survey over a flat and paved runway site, performed with an Optech ALTM 3100 sensor, showed an increase in modeled vertical errors of 5 cm, at a nadir scan orientation, to 8 cm at scan edges; for an aircraft altitude of 1200 m and half scan angle of 15°. In a survey with the same sensor, at a highly sloped glacial basin site absent of vegetation, modeled vertical errors reached over 2 m. Validation of error models within the glacial environment, over three separate flight lines, respectively showed 100%, 85%, and 75% of elevation residuals fell below error predictions. Future</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015AGUFM.B43E0607B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015AGUFM.B43E0607B"><span id="translatedtitle">A Bayesian Hierarchical Model for Spatio-Temporal Prediction and Uncertainty Assessment Using Repeat Li<span class="hlt">DAR</span> Acquisitions for the Kenai Peninsula, AK, USA</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Babcock, C. R.; Andersen, H. E.; Finley, A. O.; Cook, B.; Morton, D. C.</p> <p>2015-12-01</p> <p>Models using repeat Li<span class="hlt">DAR</span> and field campaigns may be one mechanism to monitor carbon storage and flux in forested regions. Considering the ability of multi-temporal Li<span class="hlt">DAR</span> to estimate growth, it is not surprising that there is great interest in developing forest carbon monitoring strategies that rely on repeated Li<span class="hlt">DAR</span> acquisitions. Allowing for sparser field campaigns, Li<span class="hlt">DAR</span> stands to make monitoring forest carbon cheaper and more efficient than field-only sampling procedures. Here, we look to the spatio-temporally data-rich Kenai Peninsula in Alaska to examine the potential for Bayesian spatio-temporal mapping of forest carbon storage and uncertainty. The framework explored here can predict forest carbon through space and time, while formally propagating uncertainty through to prediction. Bayesian spatio-temporal models are flexible frameworks allowing for forest growth processes to be formally integrated into the model. By incorporating a mechanism for growth---using temporally repeated field and Li<span class="hlt">DAR</span> data---we can more fully exploit the information-rich inventory network to improve prediction accuracy. Li<span class="hlt">DAR</span> data for the Kenai Peninsula has been collected on four different occasions---spatially coincident Li<span class="hlt">DAR</span> strip samples in 2004, 09 and 14, along with a wall-to-wall collection in 2008. There were 436 plots measured twice between 2002 and 2014. Li<span class="hlt">DAR</span> was acquired at least once over most inventory plots with many having Li<span class="hlt">DAR</span> collected during 2, 3 or 4 different campaigns. Results from this research will impact how forests are inventoried. It is too expensive to monitor terrestrial carbon using field-only sampling strategies and currently proposed Li<span class="hlt">DAR</span> model-based techniques lack the ability to properly utilize temporally repeated and misaligned data. Bayesian hierarchical spatio-temporal models offer a solution to these shortcomings and allow for formal predictive error assessment, which is useful for policy development and decision making.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2007AGUFM.G51B0438P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2007AGUFM.G51B0438P"><span id="translatedtitle">Li<span class="hlt">DAR</span> Acquisition for the GeoEarthScope Community</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Phillips, D. A.; Furlong, K.; Bruhn, R.; Dolan, J.; Oldow, J.; Prentice, C.; Rubin, C.; Burbank, D.; Wernicke, B.; Wesnousky, S.</p> <p>2007-12-01</p> <p>Li<span class="hlt">DAR</span> acquisition is a key component of the GeoEarthScope Initiative. Li<span class="hlt">DAR</span> provides data with a broad range of applicability to many of the EarthScope goals. A working group was convened to identify primary targets for data acquisition, rank these targets, and propose a data acquisition scheme to effectively acquire these data within the GeoEarthScope funding time frame. The Regional Targets are: a.) Northern California - including the San Andreas Fault north of Parkfield, and other major strands of the San Andreas Fault system; b.) Southern California - including the Garlock Fault, Eastern California Shear zone south of the Garlock, and the Elsinore Fault; c.) Eastern California, Walker Lane, and Basin and Range fault systems - including faults of the Eastern California Shear Zone north of the Garlock Fault; d.) Intermountain Seismic Belt - including the Wasatch Fault, Teton Fault, and Yellowstone Park area; e.) Alaska - including the Castle Mountain and Denali Faults; f.) Cascadia - including the Little Salmon fault zone in southern Cascadia, the Calawah Fault in the Washington forearc, and imagery in the Yakima Fold belt termination. The Working Group recognized that available funding would likely preclude obtaining data from all high priority sites The Working Group wrestled with several important issues that affect the data acquisition plan and the prioritization of sites. The WG tried to develop a plan that honored the primary EarthScope goals, recognizing the limited funding available. In particular, in order to maximize the coverage obtained and serve the broadest community, the WG elected to utilize relatively narrow swath widths (typically 1 km, widened to 2+km in key regions), which allowed more line-kilometers of data to be obtained. The unavoidable consequences of this choice are that areas away from the main fault strands will be unsampled. Data acquisition is underway. The Northern California acquisition (supplemented by financial support from state</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014EGUGA..1615030C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014EGUGA..1615030C"><span id="translatedtitle">Building a Li<span class="hlt">DAR</span> point cloud simulator: Testing algorithms for high resolution topographic change</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Carrea, Dario; Abellán, Antonio; Derron, Marc-Henri; Jaboyedoff, Michel</p> <p>2014-05-01</p> <p>Terrestrial laser technique (TLS) is becoming a common tool in Geosciences, with clear applications ranging from the generation of a high resolution 3D models to the monitoring of unstable slopes and the quantification of morphological changes. Nevertheless, like every measurement techniques, TLS still has some limitations that are not clearly understood and affect the accuracy of the dataset (point cloud). A challenge in Li<span class="hlt">DAR</span> research is to understand the influence of instrumental parameters on measurement errors during Li<span class="hlt">DAR</span> acquisition. Indeed, different critical parameters interact with the scans quality at different ranges: the existence of shadow areas, the spatial resolution (point density), and the diameter of the laser beam, the incidence angle and the single point accuracy. The objective of this study is to test the main limitations of different algorithms usually applied on point cloud data treatment, from alignment to monitoring. To this end, we built in MATLAB(c) environment a Li<span class="hlt">DAR</span> point cloud simulator able to recreate the multiple sources of errors related to instrumental settings that we normally observe in real datasets. In a first step we characterized the error from single laser pulse by modelling the influence of range and incidence angle on single point data accuracy. In a second step, we simulated the scanning part of the system in order to analyze the shifting and angular error effects. Other parameters have been added to the point cloud simulator, such as point spacing, acquisition window, etc., in order to create point clouds of simple and/or complex geometries. We tested the influence of point density and vitiating point of view on the Iterative Closest Point (ICP) alignment and also in some deformation tracking algorithm with same point cloud geometry, in order to determine alignment and deformation detection threshold. We also generated a series of high resolution point clouds in order to model small changes on different environments</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014AGUFM.H43D0984Y','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014AGUFM.H43D0984Y"><span id="translatedtitle">Human Impact Intertwined with Glacial Legacy: Hydro-Geomorphologic Exploration using Li<span class="hlt">DAR</span> data</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Yan, Q.; Kumar, P.</p> <p>2014-12-01</p> <p>Intensively managed landscapes (IMLs) in the Midwestern United States are heavily modified by agriculture, artificial drainage, deforestation, urbanization, and wetland destruction. These landscapes have been shaped by repeated glacial events over geologic time scales followed with rapid human modifications for agriculture and drainage that are overlaid on extremely low gradient stream networks. In this study, using Li<span class="hlt">DAR</span> data from the Upper Sangamon River Basin in Illinois, we attempt to understand how the long-term glacial legacy has shaped the landscape and what is the impact from short-term human activities, such as channel straightening and periodic dredging. Glacial and human legacy impact landscape dynamics simultaneously. Therefore, we evaluate the present-day dynamics of landscapes by attempting to address several questions. First, we explore whether the watershed is in equilibrium conditions or away from it due to human activities. Second, we study how this relates to the degree of maturity in the river valley. Moreover, we map the spatial distributions of terraces and floodplains to understand depositional and erosional history. High-resolution Li<span class="hlt">DAR</span> data is ideal for such a study as it reveals the impact of both glacial episodes and human activities. Methods used for extraction of useful information from Li<span class="hlt">DAR</span> data include the TerEx tool, Stream Profiler, and Hec-GeoRas, among others. We analyze the terrace and floodplain geomorphic features, quantify stream sinuosity, and cross section geometries. An integral method is built based on stream power incision model to obtain sub-basin steady state condition. These features help to reveal local and global watershed properties. A bounded relationship between terraces/floodplains, sinuosity, cross section maturity, as well as sub-basin equilibrium condition is explored. In general, we find that the glacial legacy and present-day human activity have opposed each other in regards to the sub-basin equilibrium</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2009EGUGA..11.7553V&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2009EGUGA..11.7553V&link_type=ABSTRACT"><span id="translatedtitle">Applying modified high resolution airborne Li<span class="hlt">DAR</span> DTM for floodplain mapping</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Vetter, M.; Jochem, A.; Franke, M.; Schöberl, F.; Stötter, J.; Werthmann, M.</p> <p>2009-04-01</p> <p>Today, airborne Li<span class="hlt">DAR</span> derived digital terrain models (DTM) are used in the research context and various scientific disciplines. In hydrology such high resolution DTMs are used for computing flood simulations, calculating roughness maps, floodplain mapping, etc. The presented approach outlines the strength of a Li<span class="hlt">DAR</span> derived DTM (1m) in comparison to a photogrammetric derived DTM (10m). By implementing an interpolated river bed model, which is derived by using terrestrial measured river cross sections and hence modifying the high resolution DTM for hydraulic task floodplain mapping and modeling routines, could be improved. The river bed interpolation routine includes an automatic bridge detection algorithm to delete bridge pillars in the relevant river cross sections. Furthermore, the position of riverbanks, which are a contributing factor in the field of hydraulic modeling and influence the results of the hydraulic simulations, can be detected. Once the DTM is modified, river cross profiles can be extracted directly on each position along the river axis and can be used as input for hydraulic models. In this study the software HEC-RAS is used to calculate different floodplain areas on the basis of the HQ30, HQ100 and HQ200 flood scenarios, which are calibrated on key data of the flood in August 2005. The comparison of the floodplain area in the city of Innsbruck (Tyrol, Austria), modeled on the basis of a modified Li<span class="hlt">DAR</span> derived DTM, with those from the HORA study (Hochwasserrisikozonierung Austria), shows remarkable differences. These differences result from (i) the different hydraulic modeling methods and (ii) the used DTMs, which HORA does not consider flood protection measures. The results show that the resolution of the used DTM is the determining factor for modeling adequate floodplain areas whereas the applied hydraulic model has secondary effects. The grade of accuracy attained by this approach is reflected by the numbers ,of flooding affected buildings (e</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014AGUFM.C43D0417Z','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014AGUFM.C43D0417Z"><span id="translatedtitle">Cross-sites analysis of snowpack depth from Li<span class="hlt">DAR</span> in Southern Sierra Nevada</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Zheng, Z.; Kirchner, P. B.; Bales, R. C.; Glaser, S. D.</p> <p>2014-12-01</p> <p>To investigate on the differences and similarities of snow depth spatial variability over different watershed areas, five sites in Southern Sierra Nevada Critical Zone Observatory were selected for creating the snow depth maps using the snow-on and snow-off Li<span class="hlt">DAR</span> datasets. The snow-on data were collected during the snow-peak time in 2010, while the snow-off data were collected during the summer in the same year. By subtracting the digital elevation models (DEM) of the snow-off data from the snow-on point clouds, snow-depth maps for these sites were created. Furthermore, canopy height, slope, and aspect are also appended with the snow-depth for digging out the impact on the snow distribution from these topography features. From the results, the snow depth in the open area increases at 14-15 cm/100 m elevation increasing is consistent across areas in the elevation range from 1850m to 2700m, while The results under the canopy presented an increasing rate about 2 cm/100 m higher but with around 20 cm lower of snow depth compared to that in the open area. Other than elevation, aspect also has a tremendous effect on snow distribution with the result showing that the ground facing to the northeast direction always having more snow accumulated than other areas regardless of vegetation existence. Even though the results reveal strong consistency of the vegetation impact on the snow depth across sites, only about 35% of total area is under canopy in forested areas and less than 30% of Li<span class="hlt">DAR</span> beams could be returned from the ground under the canopy. The Li<span class="hlt">DAR</span> might overestimate the snowpack volume but is still an important index for blending with ground data and data from remote-sensing satellites. Also, implied from the tight connection between snow depth and aspect, it is suggested that solar radiation, wind speed and direction, temperature, as well as other environmental factors are interacting with topography features and playing important roles in snowpack redistribution</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2016EGUGA..1814595B&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2016EGUGA..1814595B&link_type=ABSTRACT"><span id="translatedtitle">Long-term persistence of throughfall yield assessed by small footprint Li<span class="hlt">DAR</span> data</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Bischoff, Sebastian; Levia, Delphis F.; Nieschulze, Jens; Schulz, Florian; Michalzik, Beate</p> <p>2016-04-01</p> <p>Throughfall (TF) represents an important relocation mechanism for the spatial distribution of intercepted precipitation and hence associated nutrients in wooded ecosystems. To date, a broad range of studies showed that the spatial patterns of TF distribution exhibit a pronounced temporal stability. These studies, however, have examined TF temporal stability at the tree scale or they were computed from event-based data. Here, we seek to evaluate the utility of temporally aggregated TF data at one, three, and six year intervals to determine whether such long-term TF monitoring data could serve as the basis for TF temporal persistence measurements for both beech and spruce forests. In addition, we examine the temporal persistence of TF in relation to small footprint Li<span class="hlt">DAR</span> data. In context of the German Science Foundation (DFG) founded "Biodiversity Exploratories" (www.biodiversity-exploratories.de) we studied water-bound nutrient fluxes on a set of three differently managed forest plots (spruce plantation, age class forest beech, unmanaged beech) in central Germany throughout the vegetation periods of 2010 - 2015. For long-term monitoring purposes, TF samples were collected in biweekly routine sampling intervals using X-shaped transects of 20 bulk samplers (axis length 32 m) per experimental plot. In this study, we aim to identify canopy structural parameters explaining the temporal patterns observed. We therefore used small footprint Li<span class="hlt">DAR</span> (Light Detection And Ranging) data to calculate several canopy structural parameters on base of a gridded canopy model (grid cell resolution = 0.75 m). As Li<span class="hlt">DAR</span> allows a three-dimensional description of the complex forest canopy structure it might help to extend our understanding of complex canopy processes influencing the spatial dispersal of precipitation water, and hence associated nutrient fluxes, in wooded ecosystems. Preliminary data analysis reveals that normalized TF values identify a number of TF collectors on each of the</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014PhDT........81K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014PhDT........81K"><span id="translatedtitle">Assessing Surface Fuel Hazard in Coastal Conifer Forests through the Use of Li<span class="hlt">DAR</span> Remote Sensing</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Koulas, Christos</p> <p></p> <p>The research problem that this thesis seeks to examine is a method of predicting conventional fire hazards using data drawn from specific regions, namely the Sooke and Goldstream watershed regions in coastal British Columbia. This thesis investigates whether Li<span class="hlt">DAR</span> data can be used to describe conventional forest stand fire hazard classes. Three objectives guided this thesis: to discuss the variables associated with fire hazard, specifically the distribution and makeup of fuel; to examine the relationship between derived Li<span class="hlt">DAR</span> biometrics and forest attributes related to hazard assessment factors defined by the Capitol Regional District (CRD); and to assess the viability of the Li<span class="hlt">DAR</span> biometric decision tree in the CRD based on current frameworks for use. The research method uses quantitative datasets to assess the optimal generalization of these types of fire hazard data through discriminant analysis. Findings illustrate significant Li<span class="hlt">DAR</span>-derived data limitations, and reflect the literature in that flawed field application of data modelling techniques has led to a disconnect between the ways in which fire hazard models have been intended to be used by scholars and the ways in which they are used by those tasked with prevention of forest fires. It can be concluded that a significant trade-off exists between computational requirements for wildfire simulation models and the algorithms commonly used by field teams to apply these models with remote sensing data, and that CRD forest management practices would need to change to incorporate a decision tree model in order to decrease risk.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/27608025','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/27608025"><span id="translatedtitle">Testing the Suitability of a Terrestrial 2D Li<span class="hlt">DAR</span> Scanner for Canopy Characterization of Greenhouse Tomato Crops.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Llop, Jordi; Gil, Emilio; Llorens, Jordi; Miranda-Fuentes, Antonio; Gallart, Montserrat</p> <p>2016-01-01</p> <p>Canopy characterization is essential for pesticide dosage adjustment according to vegetation volume and density. It is especially important for fresh exportable vegetables like greenhouse tomatoes. These plants are thin and tall and are planted in pairs, which makes their characterization with electronic methods difficult. Therefore, the accuracy of the terrestrial 2D Li<span class="hlt">DAR</span> sensor is evaluated for determining canopy parameters related to volume and density and established useful correlations between manual and electronic parameters for leaf area estimation. Experiments were performed in three commercial tomato greenhouses with a paired plantation system. In the electronic characterization, a Li<span class="hlt">DAR</span> sensor scanned the plant pairs from both sides. The canopy height, canopy width, canopy volume, and leaf area were obtained. From these, other important parameters were calculated, like the tree row volume, leaf wall area, leaf area index, and leaf area density. Manual measurements were found to overestimate the parameters compared with the Li<span class="hlt">DAR</span> sensor. The canopy volume estimated with the scanner was found to be reliable for estimating the canopy height, volume, and density. Moreover, the Li<span class="hlt">DAR</span> scanner could assess the high variability in canopy density along rows and hence is an important tool for generating canopy maps. PMID:27608025</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014JARS....8.3572N','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014JARS....8.3572N"><span id="translatedtitle">Fine-spatial scale predictions of understory species using climate- and Li<span class="hlt">DAR</span>-derived terrain and canopy metrics</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Nijland, Wiebe; Nielsen, Scott E.; Coops, Nicholas C.; Wulder, Michael A.; Stenhouse, Gordon B.</p> <p>2014-01-01</p> <p>Food and habitat resources are critical components of wildlife management and conservation efforts. The grizzly bear (Ursus arctos) has diverse diets and habitat requirements particularly for understory plant species, which are impacted by human developments and forest management activities. We use light detection and ranging (Li<span class="hlt">DAR</span>) data to predict the occurrence of 14 understory plant species relevant to bear forage and compare our predictions with more conventional climate- and land cover-based models. We use boosted regression trees to model each of the 14 understory species across 4435 km2 using occurrence (presence-absence) data from 1941 field plots. Three sets of models were fitted: climate only, climate and basic land and forest covers from Landsat 30-m imagery, and a climate- and Li<span class="hlt">DAR</span>-derived model describing both the terrain and forest canopy. Resulting model accuracies varied widely among species. Overall, 8 of 14 species models were improved by including the Li<span class="hlt">DAR</span>-derived variables. For climate-only models, mean annual precipitation and frost-free periods were the most important variables. With inclusion of Li<span class="hlt">DAR</span>-derived attributes, depth-to-water table, terrain-intercepted annual radiation, and elevation were most often selected. This suggests that fine-scale terrain conditions affect the distribution of the studied species more than canopy conditions.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ars.usda.gov/research/publications/Publications.htm?seq_no_115=261338','TEKTRAN'); return false;" href="http://www.ars.usda.gov/research/publications/Publications.htm?seq_no_115=261338"><span id="translatedtitle">A categorical, improper probability method for combining NDVI and Li<span class="hlt">DAR</span> elevation information for potential cotton precision agricultural applications</span></a></p> <p><a target="_blank" href="http://www.ars.usda.gov/services/TekTran.htm">Technology Transfer Automated Retrieval System (TEKTRAN)</a></p> <p></p> <p></p> <p>An algorithm is presented to fuse the Normalized Difference Vegetation Index (NDVI) with Light Detection and Ranging (Li<span class="hlt">DAR</span>) elevation data to produce a map potentially useful for the site-specific scouting and pest management of several insect pests. In cotton, these pests include the Tarnished Pl...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://eric.ed.gov/?q=gender+AND+violence&pg=7&id=EJ896554','ERIC'); return false;" href="http://eric.ed.gov/?q=gender+AND+violence&pg=7&id=EJ896554"><span id="translatedtitle">Intimate Partner Violence and the Association with HIV Risk Behaviors among Young Men in <span class="hlt">Dar</span> Es Salaam, Tanzania</span></a></p> <p><a target="_blank" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>Maman, Suzanne; Yamanis, Thespina; Kouyoumdjian, Fiona; Watt, Melissa; Mbwambo, Jessie</p> <p>2010-01-01</p> <p>There is growing evidence of the association between gender-based violence and HIV from the perspective and experiences of women. The purpose of this study is to examine these associations from the perspective of young men living in <span class="hlt">Dar</span> es Salaam, Tanzania. A community-based sample of 951 men were interviewed, of whom 360 had sex in the past 6…</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ars.usda.gov/research/publications/Publications.htm?seq_no_115=255850','TEKTRAN'); return false;" href="http://www.ars.usda.gov/research/publications/Publications.htm?seq_no_115=255850"><span id="translatedtitle">Vegetation and slope effects on accuracy of a Li<span class="hlt">DAR</span>-derived DEM in the sagebrush steppe</span></a></p> <p><a target="_blank" href="http://www.ars.usda.gov/services/TekTran.htm">Technology Transfer Automated Retrieval System (TEKTRAN)</a></p> <p></p> <p></p> <p>This study analyzed the errors associated with vegetation cover type and slope on a Li<span class="hlt">DAR</span> derived DEM in a semiarid environment in southwestern Idaho, USA. Reference data were collected over a range of vegetation cover types and slopes. Reference data were compared to ground raster values and Root...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2016SPIE.9828E..0IF&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2016SPIE.9828E..0IF&link_type=ABSTRACT"><span id="translatedtitle">Automatic construction of aerial corridor for navigation of unmanned aircraft systems in class G airspace using Li<span class="hlt">DAR</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Feng, Dengchao; Yuan, Xiaohui</p> <p>2016-05-01</p> <p>According to the airspace classification by the Federal Aviation Agency, Class G airspace is the airspace at 1,200 feet or less to the ground, which is beneath class E airspace and between classes B-D cylinders around towered airstrips. However, the lack of flight supervision mechanism in this airspace, unmanned aerial system (UAS) missions pose many safety issues. Collision avoidance and route planning for UASs in class G airspace is critical for broad deployment of UASs in commercial and security applications. Yet, unlike road network, there is no stationary marker in airspace to identify corridors that are available and safe for UASs to navigate. In this paper, we present an automatic Li<span class="hlt">DAR</span>-based airspace corridor construction method for navigation in class G airspace and a method for route planning to minimize collision and intrusion. Our idea is to combine Li<span class="hlt">DAR</span> to automatically identify ground objects that pose navigation restrictions such as airports and high-rises. Digital terrain model (DTM) is derived from Li<span class="hlt">DAR</span> point cloud to provide an altitude-based class G airspace description. Following the FAA Aeronautical Information Manual, the ground objects that define the restricted airspaces are used together with digital surface model derived from Li<span class="hlt">DAR</span> data to construct the aerial corridor for navigation of UASs. Preliminary results demonstrate competitive performance and the construction of aerial corridor can be automated with much great efficiency.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3231514','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3231514"><span id="translatedtitle">Geometric Calibration and Radiometric Correction of Li<span class="hlt">DAR</span> Data and Their Impact on the Quality of Derived Products</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Habib, Ayman F.; Kersting, Ana P.; Shaker, Ahmed; Yan, Wai-Yeung</p> <p>2011-01-01</p> <p>Li<span class="hlt">DAR</span> (Light Detection And Ranging) systems are capable of providing 3D positional and spectral information (in the utilized spectrum range) of the mapped surface. Due to systematic errors in the system parameters and measurements, Li<span class="hlt">DAR</span> systems require geometric calibration and radiometric correction of the intensity data in order to maximize the benefit from the collected positional and spectral information. This paper presents a practical approach for the geometric calibration of Li<span class="hlt">DAR</span> systems and radiometric correction of collected intensity data while investigating their impact on the quality of the derived products. The proposed approach includes the use of a quasi-rigorous geometric calibration and the radar equation for the radiometric correction of intensity data. The proposed quasi-rigorous calibration procedure requires time-tagged point cloud and trajectory position data, which are available to most of the data users. The paper presents a methodology for evaluating the impact of the geometric calibration on the relative and absolute accuracy of the Li<span class="hlt">DAR</span> point cloud. Furthermore, the impact of the geometric calibration and radiometric correction on land cover classification accuracy is investigated. The feasibility of the proposed methods and their impact on the derived products are demonstrated through experimental results using real data. PMID:22164121</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li class="active"><span>23</span></li> <li><a href="#" onclick='return showDiv("page_24");'>24</a></li> <li><a href="#" onclick='return showDiv("page_25");'>25</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_23 --> <div id="page_24" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li class="active"><span>24</span></li> <li><a href="#" onclick='return showDiv("page_25");'>25</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="461"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/22164121','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/22164121"><span id="translatedtitle">Geometric calibration and radiometric correction of Li<span class="hlt">DAR</span> data and their impact on the quality of derived products.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Habib, Ayman F; Kersting, Ana P; Shaker, Ahmed; Yan, Wai-Yeung</p> <p>2011-01-01</p> <p>Li<span class="hlt">DAR</span> (Light Detection And Ranging) systems are capable of providing 3D positional and spectral information (in the utilized spectrum range) of the mapped surface. Due to systematic errors in the system parameters and measurements, Li<span class="hlt">DAR</span> systems require geometric calibration and radiometric correction of the intensity data in order to maximize the benefit from the collected positional and spectral information. This paper presents a practical approach for the geometric calibration of Li<span class="hlt">DAR</span> systems and radiometric correction of collected intensity data while investigating their impact on the quality of the derived products. The proposed approach includes the use of a quasi-rigorous geometric calibration and the radar equation for the radiometric correction of intensity data. The proposed quasi-rigorous calibration procedure requires time-tagged point cloud and trajectory position data, which are available to most of the data users. The paper presents a methodology for evaluating the impact of the geometric calibration on the relative and absolute accuracy of the Li<span class="hlt">DAR</span> point cloud. Furthermore, the impact of the geometric calibration and radiometric correction on land cover classification accuracy is investigated. The feasibility of the proposed methods and their impact on the derived products are demonstrated through experimental results using real data. PMID:22164121</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://files.eric.ed.gov/fulltext/EJ1079991.pdf','ERIC'); return false;" href="http://files.eric.ed.gov/fulltext/EJ1079991.pdf"><span id="translatedtitle">Provision of Vocational Skills Education to Orphans: Lessons from Orphanage Centres in <span class="hlt">Dar</span> es Salaam City, Tanzania</span></a></p> <p><a target="_blank" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>Meli, Benjamin Mbeba</p> <p>2015-01-01</p> <p>This paper utilises data from a study that investigated the efficacy of vocational skills training provided to orphans from three orphanages in Temeke District, <span class="hlt">Dar</span> es Salaam. The three orphanage centres that were studied are Kurasini National Children Home, Saudia and Don Bosco Vocational Centre. The sample comprised of 45 orphans, an official…</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/1286923','SCIGOV-STC'); return false;" h